Ferium deletes unknown file

[polycord]

I am adding an extra mod into the folder which cannot be found on Github, Modrinth or Curseforge and every time I do ferium upgrade it deletes the "unknown" file. Is there a way to prevent this or is this something that needs to be added soon?

I'm on Linux Ubuntu

[theRookieCoder]

Ferium will remove files it doesn't download; if you want to manually add mod files by yourself, you need to add it to the user folder.