MW makes it very visible in numerous places. So just hiding it in one place does not make any sense

• https://en.wikipedia.org/wiki/Special:Version
• https://en.wikipedia.org/w/api.php?action=query&meta=siteinfo&siprop=general

This would be useless unless [[Special:Version]] would also be changed

I don't think it would be useless. It would remove it from the source of millions of pages and require from anyone who wants to know the version an extra step and knowledge of the software, rather than simply viewing source.

In T270555#6704103, @spiros71 wrote:

I don't think it would be useless. It would remove it from the source of millions of pages and require from anyone who wants to know the version an extra step and knowledge of the software, rather than simply viewing source.

If they want to know, they would be able to find out trivially. It's not going to stop them if they're determined enough.

The point of security is making things harder to people (or bots) with malicious intent. That said, I am not against changing Special:Version. At the very least, it should not be accessible (or some of its critical information) to non-logged in users.

Security is hardly a trivial matter. Wikimedia may have professionals in charge of this, but there are thousands of outdated installations out there (with known vulnerabilities), and giving anyone access to the exact version just by examining the source is handing them valuable information on a platter.

If they're running old outdated, unpatched installations, fixing it in newer versions doesn't help if they're never going to upgrade anyway

https://en.wikipedia.org/wiki/Security_through_obscurity

Security through obscurity (or security by obscurity) is the reliance in security engineering on design or implementation secrecy as the main method of providing security to a system or component. Security experts have rejected this view as far back as 1851, and advise that obscurity should never be the only security mechanism.

In T270555#6704124, @spiros71 wrote:

The point of security is making things harder to people (or bots) with malicious intent. That said, I am not against changing Special:Version. At the very least, it should not be accessible (or some of its critical information) to non-logged in users.

Most wikis allow free and open signup. So you're adding a minor hurdle that, again, is not going to stop them if they're determined enough.

I use Special:Version as an active mediawiki developer all the time. Just sayin'.

Oh, and Special:Version also gives credit to all of our active developers, which has a social importance which shouldn't be underestimated.