TYPO3 Core

Can you please post exact steps to reproduce for a xamp setup?

How can it fail with <IfModule mod_expires.c>? Or are there .htaccess somewhere, which have Expires commands not wrapped it IfModule?

I just checked all .htaccess files in the Core: There is none which uses expires commands outside of <IfModule mod_expires.c>.
I also use XAMPP and mod_expires is deactivated. I never had the problem Olly reports here.

The same was a problem if rewrite commands were not put inside <IfModule mod_rewrite.c>...</IfModule>. This was the case and has been fixed in #23799.

You could however create this kind of problem, if you activated the lines beginning with "mod_gzip_item_exclude...." which you find at the end of misc/advanced_htaccess. If you use this on Apache2.x, where mod_gzip was replaced by mod_deflate, you get a Server Error 500.
But these lines are
- deactivated by default and
- activating them on newer servers would be a configuration error.
However they are still kind of recommended as they are part of the Core.

So there are two things we should do:
- We should add a section with the lines needed for mod_deflate.
- AND put the lines on compression inside <IfModule mod_gzip.c>...</IfModule> and <IfModule mod_deflate.c>...</IfModule> respectivelly.

Christopher, could you provide a patch for this, please?

Yes, the patch is attached and pending in Core List.

Committed v3 to trunk rev. 9445.