Currently, on all loads, when mw.config is set it includes an option wgCommentByteLimit that is always null. Per codesearch, this option is never used: https://codesearch.wmcloud.org/search/?q=CommentByteLimit&i=nope&files=&excludeFiles=&repos= I propose removing it.

History:
First added in T185948: Update web UI for increased comment length as being either 255 or null, depending on the state of $wgCommentTableSchemaMigrationStage
In T166733: Deploy refactored comment storage when the migration state was removed, wgCommentByteLimit was changed to always be null
In rMW64bc98a56c84: Input length limit: Remove uses of wgCommentByteLimit the remaining uses of the config in core JS were removed. At the time, @Jdforrester-WMF
said

Should also remove from VE. (And a patch to remove it from RL, but Timo will probably want us to be nice to gadget owners and announce that again.)

In rEVED8a7860398832: Drop support for wgCommentByteLimit, hard-coded null in MW nowadays the VE use was removed.

I was unable to find a mention when searching tech news, but per global search its unused in onwiki code already, https://global-search.toolforge.org/?q=wgCommentByteLimit&namespaces=&title=