The backslash wasn't properly escaped, and "\." is apparently equal to
".". So it's accidentally filtering out these valid file names (in
Nixpkgs):
trace: excluding clfswm
trace: excluding larswm
trace: excluding mkpasswd
While at it, turn the file filter stricter to what it was before
e2589b3ca22c93029051efcde62aa773fe3085b4. That is, the file name must
start with a dot: '.swp', '.foo.swo' are filtered but 'bar.swf' is not.
9275c3387e