With Linux Mint 19.2, the Noto font-family has been abandoned in favour of the Ubuntu one. While it does look decent (and likely has the better licensing status – didn’t research that), I’m personally not a particular fan of it and preferred Noto.

Of course it can be changed back rather easily, but the Cinnamon panel stuck with Ubuntu when using the default Linux Mint theme. No problem however, since Cinnamon uses CSS for configuration stuff like this.

The responsible file is /usr/share/themes/Linux Mint/cinnamon/cinnamon.css. Simply replace Ubuntu in line 6 with "Noto Sans"  (or whatever font you prefer) so it looks like this:
font-family: Ubuntu, sans-serif;
You can also change the font-size in the line below, if you desire.

I’d recommend to do this on a copy of the original theme, just to be safe. Simply follow these steps in a terminal:
1. sudo cp -r /usr/share/themes/Linux\ Mint /usr/share/themes/Linux\ Mint\ Noto
2. sudo nano /usr/share/themes/Linux\ Mint\ Noto/cinnamon.css
3. change the line as described above, save the file
4. in the GUI, go to the theme menu, select „Linux Mint Noto“