Added manjaro linux notes to the knowledge base

knowledge base/manjaro linux.md

@@ -0,0 +1,38 @@
+# Manjaro GNU/Linux
+
+## Repositories
+
+To ensure continued stability and reliability, Manjaro uses its own dedicated software branches rather than relying on those provided by Arch:
+
+- **unstable**: synced several times a day with Arch's package releases; only a subset of them are modified to suit Manjaro; people using this branch need to have the skills to get themselves out of trouble; thanks to the feedback from these users, many issues are caught and fixed at this level; the very latest software is be located here, and using this branch is usually safe but - in rare cases - may cause issues with your system
+- **testing**: this branch is the second line of defense; users living in this branch refine the work done by users in the _unstable_ branch by providing further feedback on the packages they receive as updates
+- **stable**: packages which land here have gone through roughly a couple of weeks testing by users using the _unstable_ and _testing_ branches; these packages are usually free of any problems
+
+One can use the [branch comparison] tool to check in what branch a package is available.
+
+## Printing
+
+```shell
+pamac install manjaro-printer
+sudo gpasswd -a ${USER} sys
+sudo systemctl enable --now cups.service
+
+# configure printers in ui
+pamac install system-config-printer
+```
+
+## Further readings
+
+- [Branch comparison]
+- [Switching branches]
+- [Printing]
+
+[branch comparison]: https://manjaro.org/branch-compare
+[printing]: https://wiki.manjaro.org/index.php/Printing
+[switching branches]: https://wiki.manjaro.org/index.php/Switching_Branches
+
+## Sources
+
+- [Kde Plasma 5.23 not updating]
+
+[kde plasma 5.23 not updating]: https://forum.manjaro.org/t/kde-plasma-5-23-not-updating/88297/4