The camera allows you to store the details of up to 10 manual focus lenses and store the information in the EXIF data. This is a boon to those like me who use many of the older lenses and has to remember to make a note of the lens used while out photographing. With this new method you just select from the list you created, which lens you are using and then just take photographs.
The "Tamron 35-70mm f3.5 CF Macro" lens used to take my selfie is one of the sharpest manual zooms I have, click on the link to read more about this lens.
At first, I used to edit the lens name to show if I was using a teleconverter or focal reducer but I now mostly just edit the fStop and focal length fields, for instance when using the Teleconverter I would enter the new focal length and aperture, eg:
The "Tamron 200mm f3.5" with:
2x Teleconverter : FL 400mm, f7.0
3x Teleconverter : FL 600mm, f10.5
6x TC, 2x + 3x : FL 1200mm, f21.0
Focal Reducer : FL 144mm, f2.52
I find it much easier to just change the two fields rather than edit the lens name as well.
The images below were taken rather quickly using the "Tokina SZ-X 60-300mm f4-5.6" manual zoom attached to the E-M1 II: