Hi @ChristianFerrer, thanks for taking the time to report this! Please see https://www.mediawiki.org/wiki/Help:Locating_broken_scripts for more information.
Gadgets are local on-wiki content. Local content is managed independently on each wiki, by each wiki community themselves.
Phabricator is mostly used for MediaWiki, MediaWiki extensions, or server configuration, or by developers and teams to organize what they plan to work on.
If you are looking for help with the local code on a wiki, please see https://meta.wikimedia.org/wiki/Small_wiki_toolkits#Ask_your_technical_questions instead.
This needs fixing on the local wiki. Hence I am closing this task here - thanks for your understanding!
The problem here is wgNamespaceNumber is not defined. You can see this by following https://www.mediawiki.org/wiki/Help:Locating_broken_scripts :
https://species.wikimedia.org/wiki/MediaWiki:Gadgets-definition implies that the code to fix is at https://species.wikimedia.org/wiki/MediaWiki:Gadget-TemplateTab.js
Thanks! @ChristianFerrer: For the next potential steps, if you would like to take them:
As per https://www.mediawiki.org/wiki/Gadget_kitchen , Gadgets are managed by interface administrators.
However https://species.wikimedia.org/wiki/Special:ListUsers/interface-admin lists no interface admins.
In that case https://meta.wikimedia.org/wiki/Interface_administrators says "If your wiki does not have interface administrators, request for interface administrator help [...] should be made on Steward requests/Miscellaneous."