Importers are dedicated to parsing files. An importer may be e.g. a PDB parser, an electron density parser, etc. Whenever an importer is loaded at startup, SAMSON adds it to the list of available importers, used in particular when opening a new file from the File menu.

If you want to start developing you own importers, please, refer to the documentation about the generating SAMSON extensions and the SAMSON tutorials page for more information about writing new importers for SAMSON.