This picture posted in the dpreview Leica forum seems to be a prototype of a Leica Vario-Elmar-M 28-75mm f/3.4-5.6 ASPH lens. The poster (Dr. Ulrich Rohde) is known to be a tester for Leica equipment. I have no idea if this is an old lens prototype or a new upcoming lens. I asked on social media a week ago and did not get any results.
Update: this is an authentic prototype Leica lens based on the design of the X-Vario zoom. Only 3 lenses were produced (source).
This Leica Vario-Elmar-M 28-75mm f/3.4-5.6 ASPH lens is not to be confused with the already existing WATE (Tri Elmar 16-18-21) and MATE (Tri Elmar 28-35-50) – it is labeled as “Vario” which in Leica’s language means a real zoom lens – this is confirmed also in the dpreview comments section:































