You can even put it back in the menus:
Edit the pluginrc file and:
- locate the string "_Sharpen..."
- replace the "0" in the next line by "1"
- under that line insert "(menu-path "<Image>/Filters/Enhance")"
So the file should look like:
(plug-in-def "${gimp_plug_in_dir}/plug-ins/sharpen/sharpen" 0
(proc-def "plug-in-sharpen" 1
"Make image sharper (less powerful than Unsharp Mask)"
"This plug-in selectively performs a convolution filter on an image."
"Michael Sweet <mike@easysw.com>"
"Copyright 1997-1998 by Michael Sweet"
"1.4.2 - 3 June 1998"
"_Sharpen..."
1
(menu-path "<Image>/Filters/Enhance")
(icon icon-name -1 "")
"RGB*, GRAY*"
4 0
(proc-arg 0 "run-mode" "The run mode { RUN-INTERACTIVE (0), RUN-NONINTERACTIVE (1) }")
(proc-arg 13 "image" "Input image")
(proc-arg 16 "drawable" "Input drawable")
(proc-arg 0 "percent" "Percent sharpening (default = 10)")))
This will even survive changes in other plugins that would cause the pluginrc file to be updated.