gedit has this nice feature where it asks you what character set encoding a document is in if it can’t decide this for itself. I’m not familiar with the mechanism that is being used for this, but it probably has something to do with ninja badgers, character counting and a telepathic link to the borg collective. The problem is that if it has to give up on guessing what the file is, there’s no way to force the file to be opened as any file type at all. I encountered this when trying to access some old data that had trailing NULL characters at the end of the file. The problem is that there’s no ‘mangle it to this file type and show it to me‘ option.