A boardview (component placement) file (board 6050A2307301). Shared as “MAINZ10 6050A2307301 MB AX1 F2B.F2B” — a .f2b file, 1.67 MB.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @ShareMan_Electronic_Files. Enginerys does not host this file.
How to open a .f2b file
Boardview exported from Unisoft ProntoPLACE, occasionally used for MSI and industrial boards.
OpenBoardViewUnisoft ProntoPLACE viewer