By default, all software supports multiple file extensions. Portal 2 supports at least 2 different file extensions. The basic files that Portal 2 supports are .VPK. However, not all of the extensions listed on the list are always used to save the effects of work in Portal 2. Very often, files with such extensions are used as source data files used by Portal 2.
Portal 2 can be used to convert file formats between the file extensions listed below. You can open a file with one of the file extensions below via Portal 2 and try to save it in another file format, also supported by Portal 2.