I noticed awhile back when trying to email someone a contact from my address book that the 'Email Contact Card' (or whatever the appropriate option was) is now gone from my Share menu in the Address Book.
Now my only options for sharing a contact are: AirDrop Card, Message Card, More...
I tried looking in the Extensions preferences. Mail is in there, but disabled.

I also looked up a couple of related discussions here, such as If sharing options and Markup are missing after you install OS X Yosemite - Apple Support
but that failed to work.
Anyone have any ideas on how to restore this? It was a handy feature...
Address Book / Contacts, OS X El Capitan (10.11.3)