Instructions for install and run Flatpak files are the same as Ubuntu?

[aug7744]

Hello.
Thanks for reading my topic.
I want run an flatpak file so was downloaded an flatpak ( HandBrake-1.5.1-x86_64.flatpak ) for test.
Flatpak was installed from PPA.

After was done an command
flatpak install --bundle HandBrake-1.5.1-x86_64.flatpak

Thus was showed some details about need download dependencies and 2 warnings

Info: runtime org.gnome.Platform branch 41 is end-of-life, with reason:
The GNOME 41 runtime is no longer supported as of September 17, 2022. Please ask your application developer to migrate to a supported platform.
Info: applications using this runtime:
fr.handbrake.ghb

Info: runtime org.freedesktop.Platform.GL.default branch 21.08 is end-of-life, with reason:
org.freedesktop.Platform 21.08 is no longer receiving fixes and security updates. Please update to a supported runtime version.
Info: applications using this runtime:
fr.handbrake.ghb

Lubuntu use LXQT and Ubuntu use GNOME … However Lubuntu has any GNOME component to run software requiring GNOME ?
The warning above “The GNOME 41 runtime is no longer supported” is because not is possible in Lubuntu use GNOME ?

Flatpaks run in Lubuntu ? Which commands and dependencies need to be installed to run flatpaks in Lubuntu ? Only flatpak is enough ?

Have an nice week.

[eeyore]

I took a look at Discover and although I have the flatpak backend for it, Handbrake version 1.8.2+ds1-1 was presented as available via apt and/or from Ubuntu; for Lubuntu 24.10 and 1.7.2+ds1-1build2 for Lubuntu 24.04 (also from Ubuntu, no flatpak). This doesn’t mean there isn’t a flatpak version of handbrake but, there’s probably a reason the interface didn’t present it. What version of Lubuntu are you running?