Connectors Content repository

below are the default Connectors found in SharePoint.

Bcs – Business Connectivity Services (internal protocol)
Bcs2 – Business Connectivity Services URLs (internal protocol)
File – File shares
http – Web sites
https – Web sites over Secure Sockets Layer (SSL)
Notes – Lotus Notes databases
Rb – Exchange public folders for versions prior to Microsoft Exchange Server 2003
Rbs – Exchange public folders over SSL for versions prior to Exchange Server 2003
Sps – People profiles in Microsoft Office SharePoint Portal Server 2003
Sps3 – People profiles in Microsoft Office SharePoint Server 2007
Sps3s – People profiles in Office SharePoint Server 2007 over SSL
Spss – People profiles in SharePoint Portal Server 2003 over SSL
Sts3 – Windows SharePoint Services 3.0 and Office SharePoint Server 2007 sites
Sts3s – Windows SharePoint Services 3.0 and Office SharePoint Server 2007 sites over SSL
Sts4 – Microsoft SharePoint Foundation 2010, SharePoint Server 2010, SharePoint Foundation 2013, SharePoint Server 2013, and SharePoint Server 2016 sites
Sts4s – SharePoint Foundation 2010, SharePoint Server 2010, SharePoint Foundation 2013, SharePoint Server 2013, and SharePoint Server 2016 sites over SSL.