https://xmlchallenge.com/facts

1<!doctype html>
2<html lang="en">
3<head>
4<meta charset="utf-8">
5<meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
6<title>XML Facts &amp; Stats — XMLChallenge.com</title>
7<meta name="description" content="7 fact-checked XML facts with answers and explanations. Test yourself in the free daily round on XMLChallenge.com.">
8<link rel="canonical" href="https://xmlchallenge.com/facts">
9<meta name="robots" content="index,follow,max-image-preview:large">
10<meta name="theme-color" content="#ffffff">
11<meta property="og:type" content="website">
12<meta property="og:site_name" content="XMLChallenge.com">
13<meta property="og:title" content="XML Facts &amp; Stats — XMLChallenge.com">
14<meta property="og:description" content="7 fact-checked XML facts with answers and explanations. Test yourself in the free daily round on XMLChallenge.com.">
15<meta property="og:url" content="https://xmlchallenge.com/facts">
16<meta property="og:image" content="https://xmlchallenge.com/img/hero.jpg">
17<meta property="og:image:width" content="1200">
18<meta property="og:image:height" content="627">
19<meta property="og:image:alt" content="Close-up photograph of a CSS3 logo sticker held by a person with blurred background.">
20<meta name="twitter:card" content="summary_large_image">
21<link rel="icon" href="/favicon.svg" type="image/svg+xml">
22<link rel="preconnect" href="https://fonts.googleapis.com"><link rel="preconnect" href="https://fonts.gstatic.com" crossorigin><link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Bricolage+Grotesque:opsz,[email protected],600;12..96,700;12..96,800&family=Figtree:wght@400;500;600;700&family=JetBrains+Mono:wght@500;700&display=swap">
23<link rel="stylesheet" href="/assets/app.6.2.0.css">
24<style>:root{--accent:#7d53dd;--accent-soft:#f2eefc}</style>

25<script type="application/ld+json">{"@context":"https://schema.org","@type":"Quiz","name":"XML facts \u0026 stats","about":"XML","url":"https://xmlchallenge.com/facts","publisher":{"@type":"Organization","name":"XMLChallenge.com","url":"https://xmlchallenge.com/"},"hasPart":[{"@type":"Question","name":"What is XML mainly designed to do?","acceptedAnswer":{"@type":"Answer","text":"Store and transport structured data. XML describes data in a self-describing, plain-text format that programs can exchange."}},{"@type":"Question","name":"What characters enclose XML tags?","acceptedAnswer":{"@type":"Answer","text":"Angle brackets \u003c \u003e. XML tags look like \u003cname\u003e, using angle brackets."}},{"@type":"Question","name":"Which organization published the XML standard?","acceptedAnswer":{"@type":"Answer","text":"W3C. The World Wide Web Consortium (W3C) published the XML 1.0 recommendation."}},{"@type":"Question","name":"Which is a valid empty element in XML?","acceptedAnswer":{"@type":"Answer","text":"\u003citem/\u003e. An empty element can be written with a self-closing tag ending in /\u003e."}},{"@type":"Question","name":"What does XSD stand for?","acceptedA

25nswer":{"@type":"Answer","text":"XML Schema Definition. An XSD file defines the allowed structure and data types of an XML document."}},{"@type":"Question","name":"What is XPath used for?","acceptedAnswer":{"@type":"Answer","text":"Selecting nodes in an XML document. XPath is a query language for navigating and selecting parts of an XML tree."}},{"@type":"Question","name":"Which entity reference represents the ampersand character in XML?","acceptedAnswer":{"@type":"Answer","text":"\u0026amp;. Because \u0026 starts entity references, a literal ampersand is written as \u0026amp;."}}]}</script>

25

26<script type="application/ld+json">{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"XMLChallenge.com","item":"https://xmlchallenge.com/"},{"@type":"ListItem","position":2,"name":"Facts \u0026 stats","item":"https://xmlchallenge.com/facts"}]}</script>

26

27<script type="application/json" id="boot">{"v":"6.2.0","host":"xmlchallenge.com","brand":"XMLChallenge.com","hub":false,"preview":false,"topic":"ai","badges":{"first_round":{"name":"First Round","desc":"Finish your first daily round."},"flawless":{"name":"Flawless","desc":"Answer every question in a round correctly."},"lightning":{"name":"Lightning","desc":"A perfect round in under 25 seconds."},"on_a_roll":{"name":"On a Roll","desc":"Play 3 days in a row."},"week_warrior":{"name":"Week Warrior","desc":"Play 7 days in a row."},"unbreakable":{"name":"Unbreakable","desc":"Play 30 days in a row."},"explorer":{"name":"Explorer","desc":"Play daily rounds in 5 different arenas."},"globetrotter":{"name":"Globetrotter","desc":"Play daily rounds in 25 different arenas."},"polymath":{"name":"Polymath","desc":"Play daily rounds in 5 different topics."},"in_the_arena":{"name":"In the Arena","desc":"Join your first challenge."},"finisher":{"name":"Finisher","desc":"Complete a challenge."},"recruiter":{"name":"Recruiter","desc":"Invite a friend who finishes a round."},"captain":{"name":"Captain","desc":"Invite 5 friends who finish a round."},"podium":{"name":"Podium","desc":"Finish a day in an arena's top 3."},"challenger":{"name":"Challenger","desc":"Reach level 10."},"saved":{"name":"Profile Saved","desc":"Save your progress with an email."}},"page":"facts"}</script>

27

28<script src="/assets/app.6.2.0.js" defer></script>

28

29<script src="https://analytics.vnoc.com/tracker.js" data-domain="xmlchallenge.com" defer></script>

29
30</head>
31<body class="">
32<a class="skip" href="#main">Skip to content</a>
33<header class="nav">
34  <div class="nav-in">
35    <a class="brand" href="/" aria-label="XMLChallenge.com home">
36    <span class="brand-mark" aria-hidden="true"><svg viewBox="0 0 32 32" width="32" height="32"><rect x="1" y="1" width="30" height="30" rx="9" class="mark-bg"/><path d="M10 22.5l6-13 6 13M12.6 17h6.8" class="mark-a"/></svg></span>
37    <span class="brand-text"><span class="brand-name">XMLChallenge.com</span><span class="brand-sub">An eCorp Venture</span></span>
38  </a>
39    <nav class="nav-links" aria-label="Main"><a href="/#play">Play</a><a href="/facts" aria-current="page">Facts</a><a href="/#challenges">Challenges</a><a href="/#leaderboard">Leaderboard</a></nav>
40    <a class="chip-player" id="playerChip" href="/me" aria-label="Your profile">
41      <span class="lvl-ring" data-lvl-ring><svg viewBox="0 0 36 36" width="34" height="34"><circle cx="18" cy="18" r="15" class="ring-track"/><circle cx="18" cy="18" r="15" class="ring-fill" data-ring-fill style="stroke-dasharray:0 100"/></svg><b data-lvl>1</b></span>
42      <span class="chip-meta"><span class="chip-handle" data-handle>Guest</span><span class="chip-streak" data-streak-chip><svg viewBox="0 0 24 24" width="14" height="14" aria-hidden="true"><path d="M12 3c1 3.5 5 5.5 5 10a5 5 0 01-10 0c0-2.5 1.5-4 2.5-5.5.5 2 1.5 3 2.5 3 0-2.5-1-5 0-7.5z"/></svg><span data-streak>0</span></span></span>
43    </a>
44  </div>
45</header>
46<main id="main" class="page">
47  <p class="crumbs"><a href="/">← XMLChallenge.com</a></p>
48  <div class="facts-head">
49    <p class="eyebrow"><span class="dot"></span>Coding · Facts &amp; stats</p>
50    <h1>XML facts &amp; stats</h1>
51    <p class="lede">7 fact-checked facts about XML, each with the reason behind it. 5 more are in today's round and join this page after it closes.</p>
52    <div class="facts-cta"><a class="btn btn-primary" href="/#play">Play today's round</a><button class="btn btn-quiet" type="button" data-share-page>Share these facts</button></div>
53  </div>
54  <section class="facts-group"><h2>The basics</h2><div class="facts"><article class="fact"><h3>What is XML mainly designed to do?</h3><p class="fact-a"><span>Answer</span><b>Store and transport structured data</b></p><p>XML describes data in a self-describing, plain-text format that programs can exchange.</p></article><article class="fact"><h3>What characters enclose XML tags?</h3><p class="fact-a"><span>Answer</span><b>Angle brackets &lt; &gt;</b></p><p>XML tags look like &lt;name&gt;, using angle brackets.</p></article></div></section><section class="facts-group"><h2>Going deeper</h2><div class="facts"><article class="fact"><h3>Which organization published the XML standard?</h3><p class="fact-a"><span>Answer</span><b>W3C</b></p><p>The World Wide Web Consortium (W3C) published the XML 1.0 recommendation.</p></article><article class="fact"><h3>Which is a valid empty element in XML?</h3><p class="fact-a"><span>Answer</span><b>&lt;item/&gt;</b></p><p>An empty element can be written with a self-closing tag ending in /&gt;.</p></article><article class="fact"><h3>What does XSD stand for?</h3><p class="fact-a"><span>Answer</span><b>XML Schema Definition</b></p><p>An XSD file defines the allowed structure and data types of an XML document.</p></article></div></section><section class="facts-group"><h2>Expert level</h2><div class="facts"><article class="fact"><h3>What is XPath used for?</h3><p class="fact-a"><span>Answer</span><b>Selecting nodes in an XML document</b></p><p>XPath is a query language for navigating and selecting parts of an XML tree.</p></article><article class="fact"><h3>Which entity reference represents the ampersand character in XML?</h3><p class="fact-a"><span>Answer</span><b>&amp;amp;</b></p><p>Because &amp; starts entity references, a literal ampersand is written as &amp;amp;.</p></article></div></section>
55  <div class="callout callout-cta"><b>Know these cold?</b><span>Today's round is five questions like these, 20 seconds each. Your streak and level follow you to every arena.</span><a class="btn btn-primary" href="/#play">Play today's round</a></div>
56</main>
57<footer class="foot" id="network">

58  <div class="foot-in">
59    <div class="foot-brand"><a class="brand" href="/" aria-label="XMLChallenge.com home">
60    <span class="brand-mark" aria-hidden="true"><svg viewBox="0 0 32 32" width="32" height="32"><rect x="1" y="1" width="30" height="30" rx="9" class="mark-bg"/><path d="M10 22.5l6-13 6 13M12.6 17h6.8" class="mark-a"/></svg></span>
61    <span class="brand-text"><span class="brand-name">XMLChallenge.com</span><span class="brand-sub">An eCorp Venture</span></span>
62  </a><p>XMLChallenge.com is one arena in the iChallenge network. Your level, streak and badges follow you to every arena once you save your profile.</p></div>
63    <div class="foot-col"><h3>More arenas</h3><ul><li><a href="https://harlemchallenge.com/" data-arena="harlemchallenge.com">HarlemChallenge.com</a></li><li><a href="https://bargainchallenge.com/" data-arena="bargainchallenge.com">BargainChallenge.com</a></li><li><a href="https://tech-challenge.com/" data-arena="tech-challenge.com">Tech-Challenge.com</a></li><li><a href="https://llmchallenge.com/" data-arena="llmchallenge.com">LLMChallenge.com</a></li><li><a href="https://bigdatachallenge.com/" data-arena="bigdatachallenge.com">BigDataChallenge.com</a></li><li><a href="https://britainchallenge.com/" data-arena="britainchallenge.com">BritainChallenge.com</a></li></ul></div>
64    <div class="foot-col"><h3>Network</h3><ul><li><a href="https://ichallenge.com/?utm_source=xmlchallenge.com&utm_medium=network_footer" data-arena="ichallenge.com">iChallenge.com</a><span>Every arena, one profile</span></li><li><a href="https://ventureos.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">VentureOS.com</a><span>Venture operating system</span></li><li><a href="https://sportswallet.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">SportsWallet.com</a><span>Your SportTokens wallet</span></li><li><a href="https://contrib.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">Contrib.com</a><span>Contributor community</span></li><li><a href="https://savingtheworld.org/?utm_source=xmlchallenge.com&utm_medium=network_footer">SavingTheWorld.org</a><span>Impact home of the network</span></li><li><a href="https://ecoboard.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">EcoBoard.com</a><span>Florida environmental alerts</span></li><li><a href="https://alertstream.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">AlertStream.com</a><span>Alert streams for every place</span></li><li><a href="https://referrals.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">Referrals.com</a><span>Referral engine</span></li><li><a href="https://agentnews.com/?utm_source=xmlchallenge.com&utm_medium=network_footer">AgentNews.com</a><span>Agent economy news</span></li></ul></div>
65    <div class="foot-col"><h3>Arena</h3><ul><li><a href="/facts">Facts &amp; stats</a></li><li><a href="/stats">Arena stats</a></li><li><a href="/rules">Rules &amp; scoring</a></li><li><a href="/me">Your profile</a></li><li><a href="/.well-known/agent.json">Agent card</a></li><li><a href="/sitemap.xml">Sitemap</a></li></ul></div>
66  </div>
67  <div class="foot-deal"><a href="/partner" data-partner-link>Acquire or partner on XMLChallenge.com →</a></div>
68  <div class="foot-base"><span>© 2026 XMLChallenge.com · An eCorp Venture</span><span>Free to play. No purchase necessary.</span></div>
69</footer>
70<div class="toasts" id="toasts" role="status" aria-live="polite"></div>

71<script>(function(){function c(){var b=a.contentDocument||(a.contentWindow&&a.contentWindow.document);if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'a47116a3fca4e590',t:'MTc5MTQxOTk2Ng=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();</script>

71</body>
72</html>