How to list all flatpak apps that use a specific runtime

Background

I got these messages when updating:

Info: org.gnome.Platform is end-of-life, with reason: GNOME 3.24 runtime is no longer supported as of 11th January 2019. Please ask your application developer to migrate to a supported platform.
Info: org.gnome.Platform.Locale is end-of-life, with reason: GNOME 3.24 runtime is no longer supported as of 11th January 2019. Please ask your application developer to migrate to a supported platform.

As this is a runtime, I now want to find out, which app(s) is/are actually using this outdated runtime, so I can report it as a bug there.

Basically, I just want to do what the message told me… ?

Question

So, given a name of a runtime (org.gnome.Platform) and a version of a runtime (3.24) how can I list all apps that use this runtime in this specific version?

Also, please answer the simpler case without a specific version, so how can I list all apps that use a specific runtime (org.gnome.Platform)?

Tries so far

• flatpak info --show-runtime <appid> shows the runtime of a specific app… But well… I can hardly do this manually for each app.
• flatpak list --app shows all apps, but no runtime information. Even flatpak list --app --columns=all does not show something specific.
• flatpak list --runtime show all runtimes including the version (nice), but not, which apps actually make use of it.
• I can use flatpak info org.gnome.Platform//3.24 to show information about the runtime, but I have still no idea what app uses it.