bug#48307: [External] : bug#48307: Feature request: provide default keybindings to change the font size in all windows

[Drew Adams]

> and there are many libraries that reimplement
> solutions to this issue:

Except for zoom-frm.el, which dates from 2005, those
all seem to date from at least 2013.

It doesn't really look like zoom-frm.el RE-implements
this.  It also looks to be the only one that lets you
use the same commands to text-scale (zoom individual
buffers - in all of their windows) or zoom frames
(zoom all windows in a frame).

As for zooming all frames together, zoom-frm.el has
commands `zoom-all-frames-(in|out)' for that.

But when it comes to zooming all frames in some way,
the questions Eli raised seem relevant, in general.

IMO, it's particularly useful to be able to optionally
(1) zoom a buffer everywhere, so all its windows show
its text at the same size _OR_ (2) show a buffer's text
at different sizes in different windows.  Text-scaling
does (only) #1.  Frame zooming allows #2.