Currently, if I go to https://www.mediawiki.org/wiki/User:Amire80/ve-source and
edit it using VE, I can edit the content of the <source> tag. If my UI language
is Hebrew, then the <textarea> for editing the poem is RTL. I would expect it
to be always LTR by default, because source code is almost always LTR. (There are some RTL programming languages like Hebrew Logo and Arabic Alb, but these are very rare exceptions and the <source> tag doesn't support them anyway.)
This is comparable to Bug 56779, but unlike in that bug, here the request is that the direction will be explicitly set to ltr rather than the surrounding direction.
There may be other tags for which something like this would be useful, but I can't think of any at the moment.