This file will simply configure it to use the IdentityFile of this machine and import another file that has the actual host definitions at ~/Preferences/ssh/config - that is the one I sync with Syncthing. This gives a nice way to customize settings for each machine (key path and whatnot) while keeping a global file with in sync between all of them.
For reference here is ~/Preferences/ssh/config:
<span style="color:#323232;">Host *
</span><span style="color:#323232;"> IdentitiesOnly no
</span><span style="color:#323232;"> AddKeysToAgent yes
</span><span style="color:#323232;">
</span><span style="color:#323232;">host server1
</span><span style="color:#323232;"> hostname x.x.x.x
</span><span style="color:#323232;"> user xxxxx
</span><span style="color:#323232;"> port 1111
</span><span style="color:#323232;">
</span><span style="color:#323232;">host server2
</span><span style="color:#323232;"> hostname x.x.x.x
</span><span style="color:#323232;"> user xxxxx
</span><span style="color:#323232;"> port 2222
</span>