Just for the record, I checked all existing filenames at files:/srv/www/files/* and we'd need the following regexp to be able to upload them using `ent`: `/a-zA-Z0-9\-_\.~\+/`.

Example to show the need for `~` and `+` in addition to the already mentioned `_` and `-`: `libmp4v2-dev_1.9.1+svn479~dfsg0-3~oneiric1+medibuntu1_amd64.copyright`.