In terminal I ran:
defaults write com.apple.finder AppleShowAllFiles TRUE
If I CMD + SHIFT + G
/usr/local/.git I can see the folder.
However, if I CMD + SHIFT + G and go to
/usr/local I cannot see the folder.
You have to let Finder know that you want a Boolean value (true or false):
defaults write com.apple.finder AppleShowAllFiles -bool TRUE
Shift-Command-Period shows and hides the files in open/save dialogs, it might work in the main Finder.