^ is escaped, but it works with gitignore.

To test it:

mkdir test && cd test
git init
echo 'a[^b]c' > .gitignore
touch abc azc
git status -u --ignored

Notice that abc doesn't match but azc does match. pathspec's behavior with ^ is inconsistent with Git.

I read:

But I didn't understand why would you prefer to be compatible with POSIX and Python's fnmatch.translate when you could be compatible with gitignore itself. May I ask what led you to the decision to escape ^?