Try initial content.json in a script tag.

generator/src/elm-pages-js-minified.js

@@ -1 +1 @@
-module.exports = `let prefetchedPages=[window.location.pathname],initialLocationHash=document.location.hash.replace(/^#/,"");function loadContentAndInitializeApp(){let a=window.location.pathname.replace(/(\w)$/,"$1/");a.endsWith("/")||(a+="/");const b=Elm.TemplateModulesBeta.init({flags:{secrets:null,baseUrl:document.baseURI,isPrerendering:!1,isDevServer:!1,isElmDebugMode:!1,contentJson:window.__elmPagesContentJson__,userFlags:userInit.flags()}});return b.ports.toJsPort.subscribe(()=>{loadNamedAnchor()}),b}function loadNamedAnchor(){if(""!==initialLocationHash){const a=document.querySelector(\`[name=\${initialLocationHash}]\`);a&&a.scrollIntoView()}}function prefetchIfNeeded(a){if(a.host===window.location.host&&!prefetchedPages.includes(a.pathname)){prefetchedPages.push(a.pathname),console.log("Preloading...",a.pathname);const b=document.createElement("link");b.setAttribute("as","fetch"),b.setAttribute("rel","prefetch"),b.setAttribute("href",origin+a.pathname+"/content.json"),document.head.appendChild(b)}}const appPromise=new Promise(function(a){document.addEventListener("DOMContentLoaded",()=>{a(loadContentAndInitializeApp())})});userInit.load(appPromise),"function"==typeof connect&&connect(function(a){appPromise.then(b=>{b.ports.fromJsPort.send({contentJson:a})})});const trigger_prefetch=b=>{const c=find_anchor(b.target);c&&c.href&&c.hasAttribute("elm-pages:prefetch")&&prefetchIfNeeded(c)};let mousemove_timeout;const handle_mousemove=a=>{clearTimeout(mousemove_timeout),mousemove_timeout=setTimeout(()=>{trigger_prefetch(a)},20)};addEventListener("touchstart",trigger_prefetch),addEventListener("mousemove",handle_mousemove);function find_anchor(a){for(;a&&"A"!==a.nodeName.toUpperCase();)a=a.parentNode;return a}`;
+module.exports = `let prefetchedPages=[window.location.pathname],initialLocationHash=document.location.hash.replace(/^#/,"");function loadContentAndInitializeApp(){let a=window.location.pathname.replace(/(\w)$/,"$1/");a.endsWith("/")||(a+="/");const b=Elm.TemplateModulesBeta.init({flags:{secrets:null,baseUrl:document.baseURI,isPrerendering:!1,isDevServer:!1,isElmDebugMode:!1,contentJson:JSON.parse(document.getElementById("__ELM_PAGES_DATA__").innerHTML),userFlags:userInit.flags()}});return b.ports.toJsPort.subscribe(()=>{loadNamedAnchor()}),b}function loadNamedAnchor(){if(""!==initialLocationHash){const a=document.querySelector(\`[name=\${initialLocationHash}]\`);a&&a.scrollIntoView()}}function prefetchIfNeeded(a){if(a.host===window.location.host&&!prefetchedPages.includes(a.pathname)){prefetchedPages.push(a.pathname),console.log("Preloading...",a.pathname);const b=document.createElement("link");b.setAttribute("as","fetch"),b.setAttribute("rel","prefetch"),b.setAttribute("href",origin+a.pathname+"/content.json"),document.head.appendChild(b)}}const appPromise=new Promise(function(a){document.addEventListener("DOMContentLoaded",()=>{a(loadContentAndInitializeApp())})});userInit.load(appPromise),"function"==typeof connect&&connect(function(a){appPromise.then(b=>{b.ports.fromJsPort.send({contentJson:a})})});const trigger_prefetch=b=>{const c=find_anchor(b.target);c&&c.href&&c.hasAttribute("elm-pages:prefetch")&&prefetchIfNeeded(c)};let mousemove_timeout;const handle_mousemove=a=>{clearTimeout(mousemove_timeout),mousemove_timeout=setTimeout(()=>{trigger_prefetch(a)},20)};addEventListener("touchstart",trigger_prefetch),addEventListener("mousemove",handle_mousemove);function find_anchor(a){for(;a&&"A"!==a.nodeName.toUpperCase();)a=a.parentNode;return a}`;

generator/src/pre-render-html.js

@@ -33,9 +33,9 @@ module.exports =
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <script type="module">
 import userInit from"/index.js";
-window.__elmPagesContentJson__ = ${contentJsonString}
 ${elmPagesJsMinified}
     </script>
+    <script id="__ELM_PAGES_DATA__" type="application/json">${contentJsonString}</script>
     <title>${fromElm.title}</title>
     <meta name="generator" content="elm-pages v${cliVersion}">
     <link rel="manifest" href="manifest.json">

generator/static-code/elm-pages.js

@@ -18,7 +18,9 @@ function loadContentAndInitializeApp() {
       isPrerendering: false,
       isDevServer: false,
       isElmDebugMode: false,
-      contentJson: window.__elmPagesContentJson__,
+      contentJson: JSON.parse(
+        document.getElementById("__ELM_PAGES_DATA__").innerHTML
+      ),
       userFlags: userInit.flags(),
     },
   });