Ups, sorry for the mistake! sdetweil instead of jopyth :-)

And … Great work. Thank you.

pi@InfoTerminal:~/MagicMirror/modules $ git clone https://github.com/sdetweil/MMM-Buttons.git
Klone nach ‘MMM-Buttons’ …
remote: Enumerating objects: 56, done.
remote: Counting objects: 100% (4/4), done.
remote: Compressing objects: 100% (4/4), done.
remote: Total 56 (delta 0), reused 2 (delta 0), pack-reused 52
Entpacke Objekte: 100% (56/56), Fertig.
pi@InfoTerminal:~/MagicMirror/modules $ cd MMM-Buttons/
pi@InfoTerminal:~/MagicMirror/modules/MMM-Buttons $ npm install

Magic-Mirror-Module-Buttons@1.0.0 postinstall
./postinstall

/home/pi/MagicMirror/modules/MMM-Buttons
⠴ Building module: epoll, Completed: 0make: Verzeichnis „/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/epoll/build“ wird betreten
CXX(target) Release/obj.target/epoll/src/epoll.o
⠋ Building module: epoll, Completed: 0 SOLINK_MODULE(target) Release/obj.target/epoll.node
⠼ Building module: epoll, Completed: 0 COPY Release/epoll.node
make: Verzeichnis „/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/epoll/build“ wird verlassen
✔ Rebuild Complete

added 6 packages, and audited 7 packages in 5m

found 0 vulnerabilities
pi@InfoTerminal:~/MagicMirror/modules/MMM-Buttons $

https://github.com/sdetweil/MMM-Buttons

Here the same error:

pi@InfoTerminal:~/MagicMirror/modules $ git clone https://github.com/Jopyth/MMM-Buttons.git
Klone nach 'MMM-Buttons' ...
remote: Enumerating objects: 54, done.
remote: Total 54 (delta 0), reused 0 (delta 0), pack-reused 54
Entpacke Objekte: 100% (54/54), Fertig.
pi@InfoTerminal:~/MagicMirror/modules $ cd MMM-Buttons/
pi@InfoTerminal:~/MagicMirror/modules/MMM-Buttons $ npm install
npm WARN deprecated har-validator@5.1.5: this library is no longer supported
npm WARN deprecated uuid@3.4.0: Please upgrade  to version 7 or higher.  Older versions may use Math.random() in certain circumstances, which is known to be problematic.  See https://v8.dev/blog/math-random for details.
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142

> Magic-Mirror-Module-Buttons@1.0.0 postinstall
> node_modules/.bin/electron-rebuild -e ../../node_modules/electron

⠋ Searching dependency tree
An unhandled error occurred inside electron-rebuild
Could not detect abi for version 19.1.3 and runtime electron.  Updating "node-abi" might help solve this issue if it is a new release of electron

Error: Could not detect abi for version 19.1.3 and runtime electron.  Updating "node-abi" might help solve this issue if it is a new release of electron
    at Object.getAbi (/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/node-abi/index.js:36:9)
    at new Rebuilder (/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/electron-rebuild/lib/src/rebuild.js:126:48)
    at rebuildWithOptions (/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/electron-rebuild/lib/src/rebuild.js:404:23)
    at Object.doRebuild [as rebuild] (/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/electron-rebuild/lib/src/rebuild.js:427:16)
    at /home/pi/MagicMirror/modules/MMM-Buttons/node_modules/electron-rebuild/lib/src/cli.js:124:33
    at Generator.next (<anonymous>)
    at fulfilled (/home/pi/MagicMirror/modules/MMM-Buttons/node_modules/electron-rebuild/lib/src/cli.js:6:58)
npm ERR! code 255
npm ERR! path /home/pi/MagicMirror/modules/MMM-Buttons
npm ERR! command failed
npm ERR! command sh /tmp/postinstall-6787d5d5.sh

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/pi/.npm/_logs/2022-10-16T20_33_40_733Z-debug-0.log

https://github.com/sdetweil/MMM-Buttons

problem is the electron-rebuild was installed in the module folder
instead of the MM folder… so it couldn’t find the electron info

i fixed the package,json, and a made an external postinstall script
to install eb in the mm folder if not present and then npm install works