Sony A7R VI What is a FE mount? (as opposed to an E mount)

[CCRphoto]

The a7RVI uses E mount - but I've come across an interesting 3rd party lens that is FE mount - I've no idea what FE mount is so can someone help me by telling me if it will fit and work on an E mount?

 

[GvilleRick]

The FE refers to an E-mount lens that is designed for full frame cameras. You will see Sony brand lenses using the FE as well.