Though I have tried to modify \"font.size\" in classes like \"Label_control\" and \"sidebar_control\" in the Package \"Theme-Default\", the font size of the editor does not
On Ubuntu, for versions of Sublime older than 3.2, what worked for me was changing the dpi scale in Preferences > Settings — User by adding this line:
"dpi_scale": 1.10
For Sublime 3.2, you can use the following line instead:
"ui_scale": 1.10
Adjust the scale value as needed. After this change, you have to restart Sublime Text for it to take effect.