Yes it still exists, but the route to finding it has changed since version 78

• 'Menu icon (3 lines) > Options/Preferences > 'General'
• Scroll all the way to the bottom
• click on 'Config Editor' button

Note : second image below shows where it is via bottom of 'General'. However, you could use the top right search which is new, to search for config editor - I have provided an image below for this as the search is new.

It may say 'here be dragons' as a type friendly warning to be careful :)

• In top search type: pixels
• Look for this line: layout.css.devPixelsPerPx

The default is a negative number: -1.0

• Double click on that line to open a small window.
• clear all contents and type in a positive number eg: 1.25 or 1.5 or 1.75 or 2.0
• click on OK

The effects are instant, so you can easily modify as required

THANK YOU!! THANK YOU!! TB much easier to read at 1.25! Almost missed Config Editor again. Was not expecting an option to be shown in the lower right corner of the page when all other options are listed down the left margin. Again, thank you - and for the rapid response.

@ Matt layout.css.devPixelsPerPx only the Config layout bar size changes everything else stays the same