Grazie, as you have probably surmised, the plugins themselves end in ".ofx". Generally they are packaged in a ".bundle" sub-directory in the locations I had mentioned. For example:
../Magic Bullet Suite/MagicBulletLooks.ofx.bundle/Content/Win64/MagicBulletLooks.ofx
../Red Giant Universe/Universe_Utilities_Unmult_OFX.ofx.bundle/Contents/Win64/Universe_Utilities_Unmult_OFX.ofx
In addition to the two directories mentioned already, they can also be installed in any directory listed in the OFX_PLUGIN_PATH environment variable. You can find the contents of that variable (if any) by typing the following at a command line prompt (often incorrectly referred to as the DOS prompt):
(Don’t forget the two percent signs.) If no such variable exists in your environment, the echo command will just print the %OFX_PLUGIN_PATH% as if it was literal text. If, however, such a variable does exist, the echo command will print its contents instead, which will either be a single path or several paths separated by a semicolon. And if it does exist, Vegas will search the path/paths listed in the variable while searching for the OFX files (in addition to the two already mentioned). They will follow the same directory structure as those in the C:\Program Files\OFX\Plugins directory.