After some discussion on IRC it looks like Parser is a better component for this. Sorry for the noise.

Is this a desired enhancement request?

If so, is this bug a good candidate for Google Code-in?

https://www.mediawiki.org/wiki/Google_Code-In

1.) Do not propagate centering to the text, wether via bracketing or in the
align command. The former since bracketing is required to work around a known
bug, https://bugzilla.wikimedia.org/show_bug.cgi?id=43186. If that is fixed
then general bracketed centering would not be necessary and only the gallery
braketing would be disabled for caption text - this can be overridden with
center command bracketing in the individual caption text

I don't think this should be done. I think the majority of time the current behaviour is best.

2.) Add to the gallery syntax 'aligntext="left"', also "center" and "right".

Not opposed to this. (Not entirely sure if I see how useful this would be)

3.) Accept and process in the captions, in addition to "<center>...</center>
the markup "<left>...</left>" and "<right>...</right> (the latter for
completeness in right-to-left language markup). (These do not work at the
present time, I tried them.)

Thanks,

• Leonard.

Yeah, well those aren't real tags. (Blame the w3c, they only made a center)

Use <div align="left"> text </div>. You can also use the text-align css property

(In reply to comment #2)

Is this a desired enhancement request?

If so, is this bug a good candidate for Google Code-in?

https://www.mediawiki.org/wiki/Google_Code-In

I don't have strong opinions on how useful a textalign (pt 2) would be. I guess it could be a gci task.