$ curl -s https://tools.wmflabs.org/monumental | grep bundle
<script type="text/javascript" src="assets/bundle.min.js?v=17.07.02"></script></body>

No, related to relative uris.

You need to end URL with slash (https://tools.wmflabs.org/monumental/).

@Slaporte @MahmoudHashemi can we do backend redir from /monumental to /monumental/?

Same error here:

Loading failed for the <script> with source “https://fr.wiktionary.org/w/load.php?debug=false&lang=fr&modules=Spinner%2Cjquery%2Coojs%2Csite%7Cext.3d%2CeventLogging%2CnavigationTiming%2CwikimediaEvents%7Cext.centralNotice.choiceData%2Cdisplay%2CgeoIP%2CimpressionDiet%2CkvStore%2CkvStoreMaintenance%2CstartUp%7Cext.centralauth.ForeignApi%7Cext.centralauth.centralautologin.clearcookie%7Cext.echo.api%2Cinit%7Cext.eventLogging.subscriber%7Cext.uls.common%2Ceventlogger%2Cinit%2Cinterface%2Cpreferences%2Cwebfonts%7Cext.visualEditor.desktopArticleTarget.init%7Cext.visualEditor.supportCheck%2CtargetLoader%2CtempWikitextEditorWidget%2Ctrack%2Cve%7Cext.wikimediaEvents.loggedin%7Cjquery.accessKeyLabel%2CcheckboxShiftClick%2Cclient%2Ccookie%2CembedPlayer%2CgetAttrs%2ChighlightText%2CloadingSpinner%2CmwEmbedUtil%2Cspinner%2Csuggestions%2CtabIndex%2CtextSelection%2Cthrottle-debounce%2CtriggerQueueCallback%7Cjquery.uls.data%7Cmediawiki.ForeignApi%2CRegExp%2CString%2CTitle%2CUri%2Capi%2Cbase%2Ccldr%2Ccookie%2Cexperiments%2CjqueryMsg%2Clanguage%2Cnotification%2Cnotify%2CsearchSuggest%2Cstorage%2Ctemplate%2Ctoc%2Ctoolbar%2Cuser%2Cutil%2CvisibleTimeout%7Cmediawiki.ForeignApi.core%7Cmediawiki.editfont.styles%7Cmediawiki.legacy.wikibits%7Cmediawiki.libs.pluralruleparser%7Cmediawiki.page.ready%2Cstartup%7Cmediawiki.page.watch.ajax%7Cmediawiki.template.regexp%7Cmediawiki.ui.button%2Cicon%7Cmmv.bootstrap%2Chead%7Cmmv.bootstrap.autostart%7Cmw.EmbedPlayer.loader%7Cmw.MediaWikiPlayer.loader%7Cmw.MwEmbedSupport%2CPopUpMediaTransform%7Cmw.MwEmbedSupport.style%7Cmw.PopUpMediaTransform.styles%7Cmw.TMHGalleryHook.js%7Cmw.TimedText.loader%7Cschema.UniversalLanguageSelector%7Cskins.vector.js%7Cuser.defaults&skin=vector&version=09t0hjk”.

on the page https://fr.wiktionary.org/wiki/maman or any other fr.wikt page in read mode (except special pages)...
Note: only with Firefox, not with Google Chrome.

Because of that, all gadgets are disabled.

NB: also happens in en.wikt!

In T174498#4645457, @zhuyifei1999 wrote:

Not related.

I created a new task for it: T206329
Please fell free to archive/delete this conversation

Looks like a side effect of T214513 it seems.