MD3 Import-Export addon mysteriously doesn't work [No error messages] (8.2 KB)
Above is the zipped version of the addon. I got it from github:

When I install from file, you can “activate” this addon in User Preferences. However, when you go to File->Import, the option for importing md3 files is missing. I looked at Blender’s console and it shows no errors, only a “successfully installed” message.

Has the addon be updated to work with version 2.80? If not, you can use 2.79 to import, save and then open in 2.80. There are quite a few import addons that aren’t updated yet.