Global gadgets was the #1 wish on the 2016 Community Wishlist Survey.
https://meta.wikimedia.org/wiki/2016_Community_Wishlist_Survey/Categories/Bots_and_gadgets#CW2016-R001
This ticket is to investigate the problem, and determine what's feasible to do this year.
The gadgets on 30 or more wikis are as follows:
| gadget | wikis | default | total users | active users | comments |
|--|--|--|--|--|--|
| HotCat | 354 | 55 |102382 | 8971 | could be its own extension; see {T104394} |
| UTCLiveClock | 177 | 17 | 80049 | 2597 | add to the Purge extension; see [[https://github.com/Hutchy68/Purge/issues/16 | GH#16]] |
| wikEd | 155 | 16 | 76800 | 2226 | |
| edittop | 121 | 23 | 52482 | 1818 | add to core, but it's complicated; see {T2156} |
| Navigation_popups | 121 | 13 | 73751 | 1676 | |
| ReferenceTooltips | 110 | 87 | 4734 | 1224 | |
| purgetab | 106 | 28 | 26510 | 1261 | is the [[https://www.mediawiki.org/wiki/Extension:Purge | Purge extension]] |
| refToolbar | 82 | 47 | 9961 | 1088 | |
| contribsrange | 77 | 10 | 26328 | 1515 | will be mostly replaced by {T145912} |
| exlinks | 77 | 9 | 49136 | 1063 | add to core? |
| Twinkle | 67 | 17 | 44488 | 937 | |
| CleanDeleteReasons | 57 | 20 | 2273 | 204 | |
| DotsSyntaxHighlighter | 55 | 7 | 19378 | 1044 | replaced by #MediaWiki-extensions-CodeMirror? |
| popups | 54 | 10 | 18007 | 1878 | |
| charinsert | 49 | 41 | 245 | 26 | |
| removeAccessKeys | 48 | 7 | 11661 | 167 | |
| RTRC | 45 | 7 | 9951 | 581 | |
| ProveIt | 44 | 11 | 19607 | 685 | |
| Cat-a-lot | 41 | 8 | 10765 | 2351 | |
| searchFocus | 40 | 6 | 23461 | 452 | |
| GoogleTrans | 40 | 5 | 40774 | 300 | |
| HideFundraisingNotice | 40 | 7 | 25221 | 190 | |
| addsection-plus | 39 | 3 | 16765 | 369 | |
| CommentsInLocalTime | 36 | 4 | 18629 | 388 | |
| dropdown-menus | 36 | 8 | 18828 | 217 | |
| markblocked | 35 | 3 | 16652 | 1226 | |
| markAdmins | 34 | 3 | 21160 | 2712 | see {T180555} |
| modrollback | 34 | 4 | 11706 | 181 | |
| blackskin | 34 | 2 | 8672 | 13 | |
| OldDiff | 32 | 3 | 7076 | 377 | |
| RegexMenuFramework | 31 | 4 | 17628 | 167 | |
| ExternalSearch | 30 | 10 | 15786 | 87 | |