Linux: bat cache –build says “unexpected argument ‘–build’ found”

This question is about “bat”, the “cat” replacement with sysntax coloring, not about Windows .bat files.

According to the README on bat’s GitHub page as well as the man page, I should run bat cache --build when I want to add a new syntax definition. But when I do so, I get this error:

error: unexpected argument '--build' found.

Trying just bat cache says

[bat error]: ‘cache’: No such file or directory (os error 2)

but unfortunately it does not specify which file it expected to find. My assumption is that it has problems creating the cache for the first time.