An f1s file extension is related to the Alien Skin Settings Router and used for its settings files.
F1S file extension - Alien Skin Settings Router settings
What is f1s file? How to open f1s files?
File type specification:
The f1s file extension is associated with the Alien Skin Settings Router a software for Apple Mac OS X (macOS) and Microsoft Windows operating systems.
The f1s file stores settings for Alien Skin Settings Router.
This f1s file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.