I already converted it to HTMLForm.
|mediawiki/core : master||Convert Special:Export to OOUI|
|Open||None||T49145 Formally deprecate jQuery UI after we've stopped using jQuery UI in extensions and core (replacing it with OOUI).|
|Open||None||T100270 Replace use of jQuery UI and MW UI with OOUI across all Wikimedia-deployed extensions and core|
|Resolved||Esanders||T86617 VisualEditor's save dialog should use OOUI checkboxes|
|Open||None||T100161 Convert all of MediaWiki core to OOUI PHP (tracking)|
|Open||None||T107037 Convert all MW core special pages to OOUI|
|Resolved||Florian||T117753 Convert Special:Export to OOUI|
|Resolved||matmarex||T117762 There's still too much whitespace between FieldLayouts in a FieldsetLayout|
I submitted a patch for this one a while ago (https://gerrit.wikimedia.org/r/#/c/224722/), but apparently ran into some problems? I don't even remember anymore.
The massive amount of white space between checkboxes is concerning (this was also discussed in T113953). I do think the fields could be placed a bit tighter.