https://snapcraft.io/labplot is already available. Latest version: 2.6.0 :-(
2.8.1 is in Neon stable: https://invent.kde.org/neon/extras/labplot/-/blob/Neon/stable/snapcraft.yaml
2021-03-18: 2.8.1 is now available as snap (stable) on snapcraft.io. Thanks Jonathan!
2022:
Stable versions are kept in the Neon/release branches or the stable KDE git branch of your app. Unstable versions in Neon/unstable or the unstable branch of your app (usually master).
Links:
* Neon repo: https://invent.kde.org/neon/extras/labplot
* https://invent.kde.org/packaging/snapcraft-kde-applications/-/blob/Neon/release/labplot/snapcraft.yaml
* Neon snaps @Jenkins: https://build.neon.kde.org/view/Snaps/
* Metadata @ https://invent.kde.org/sysadmin/repo-metadata/projects-invent/education/labplot
* KDE@snapcraft: https://snapcraft.io/publisher/kde, https://snapcraft.io/search?q=KDE
Docs:
* https://community.kde.org/Guidelines_and_HOWTOs/Snap
* https://jriddell.org/2019/04/23/kdes-snap-packages/
* Jonathan Riddell's Talk: https://docs.google.com/presentation/d/13KVisXrlsrDXzqpr5G2llD33K7yGBwXE2DxByrbFzXM/edit?usp=sharing