In FreePcb-2, you can open the footprint library file as a project file.
Open the library with footprints (* .fpl) in the usual way by selecting the * .fpl filter in the dialog box, or drag the file to the program window. All library footprints will appear in front of you. Select the desired footprint and press F2_EDIT_FOOTPRINT to enter the footprint editor and start editing.
When you finish editing, click the save button in the main menu and save the file to the same library. To return and select the next footprint, right-click and press RETURN_TO_PCB