Where to find extensions installed folder for Google Chrome on Mac?

The default locations of Chrome's profile directory are defined at http://www.chromium.org/user-experience/user-data-directory. For Chrome on Mac, it's

~/Library/Application\ Support/Google/Chrome/Default

The actual location can be different, by setting the --user-data-dir=path/to/directory flag.
If only one user is registered in Chrome, look in the Default/Extensions subdirectory. Otherwise, look in the <profile user name>/Extensions directory.

If that didn't help, you can always do a custom search.

1. Go to chrome://extensions/, and find out the ID of an extension (32 lowercase letters) (if not done already, activate "Developer mode" first).

   

2. Open the terminal, cd to the directory which is most likely a parent of your Chrome profile (if unsure, try ~ then /).

3. Run find . -type d -iname "<EXTENSION ID HERE>", for example:

   find . -type d -iname jifpbeccnghkjeaalbbjmodiffmgedin

   Result:

   

You can find all Chrome extensions in below location.

/Users/{mac_user}/Library/Application Support/Google/Chrome/Default/Extensions

For Mac EI caption/Mac Sierra, Chrome extension folders were located at

/Users/$USER/Library/Application\ Support/Google/Chrome/Profile*/Extensions/