I don't think this is well-known and I just learned this by trying all possibilities with the camera buttons.
With the Visoflex 2 attached, press and hold the M11-D's top function button for about one second, then release it. That toggles what a normal press of that button does:
Info Profiles: cycles the EVF overlays, such as histogram/highlight warnings, focus peaking, and info displays.
OR
Magnification: activates manual magnification; use the thumbwheel to adjust zoom level.
I don't love focus peaking since it keys off contrast rather than actual resolution, especially with classic lenses where that distinction matters. So my default is just Magnification.
That said, peaking can still be useful if you're using Info Profiles: set magnification to none via the thumbwheel and rely on peaking alone with no zoom. That combination is useful depending on the lens maximum aperture.
