I noticed that some failed rendering jobs lately, all of which failed due to language / locale settings I hand’t tested yet.
Some of the jobs simply failed as my list of installed locales was missing some of those that could be selected in the “Create map” form, these should now all be installed as needed.
I also wrapped the setlocale() calls in a try…catch block now, so that unsupported locales will just make the rendering code fall back to English instead of letting rendering fail with an exception stack trace.