As seen by T253756, it is easy to mistakenly run a maintenance script from the deployment host rather than the maintenance host as their environment is so similar.
For a lot of people these two hosts are the only MediaWik-deployed hosts in production that they have shell access to.
To my knowledge, on a deployment host:
* ... there is no use case for running `foreachwiki` .
* ... there is one use case for automated/scripted running of `mwscript`, namely by Scap for generating the localisation cache. This does not need the CLI wrapper, though. I suggest letting scap run `php multiversion/MWScript.php` directly. That also means Scap is explicitly in control over whether it executes from `/srv/medaiwiki` or `/srv/medaiwiki-staging`.
* ... there is one use case for manual invocatsion of `mwscript`, namely as part of `scap update-interwiki-cache`. This has numerous other problems (per T247107), but given that this too is scripted by Scap, it would be trivial to write out the long-form here.
As such, I propose that the following are removed from the deployment host:
* `mwscript`
* `foreachwiki`
* `foreachwikiindblist`
* (any other MWScript wrappers?)
Thus making yielding a very obvious error that these are not available here. Just like when debugging a random app server in production, `php MWScript.php` can still be called directly ad-hoc if/when absolutely needed for some reason.