F10 file extension is for Dos screen text font - height 10 pixels fntcol13.zip
Similar to F10
1 - Unformatted manual page Roff/nroff/troff/groff10X - Gemini 10x printer graphics file - Bitmap graphics
123 - Lotus123 Data file
12M - Lotus123 Smartmaster file
15U - Printer font with PI font set PageMaker
1ST - Usually README.1ST text
24B - 24bit data Bitmap graphics
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