A sign/abbreviation for "magister"

Hi!

On the over 100 years old postcard

https://photos.app.goo.gl/GbwNwYbEQMjZaFgE6

you can see 2 occurences of a symbol which is explicitely explained (in
Polish) as meaning "Magister".

First question is: how do you interpret the symbol? For me it is
definitely the capital M followed by the superscript "r" (written in an
old style no longer used in Poland), but there is something below the
superscript. It looks like a small "z", but such an interpretation
doesn't make sense for me.

The second question is: are you familiar with such or a similar symbol?
Have you ever seen it in print?

The third and the last question is: how to encode this symbol in
Unicode?

Best regards

Janusz

-- 
             ,   
Janusz S. Bien
emeryt (emeritus)
https://sites.google.com/view/jsbien