MarsSeed [1] filed a request to merge plasma5-applets-thermal-monitor [2] into plasma6-applets-thermal-monitor-git [3]:
Only the Plasma6 package works now on Arch Linux. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/plasma5-applets-thermal-monitor/ [3] https://aur.archlinux.org/pkgbase/plasma6-applets-thermal-monitor-git/
