Adding plugins to a flatpak installed app?

[Alec Leamas]

On 03/05/2019 11:06, Alexander Larsson wrote:
> So, each installation (e.g. /var/lib/flatpak, and
> ~/.local/share/flatpak as well as other customly added ones) can have
> a subdirectory called "extension". In this directory you can create
> directories named $ref/$arch/$branch, and the contents of that will be
> directly visible as the content of the plugins (i.e. what would be in
> the "files" subdirectory of the deploy dir if you installed a packaged
> version of the plugins).

Which, if I get it right, makes it possible to install plugins from outside the sandbox.

But what if the application can download and install it's own plugins, like e. g. web browsers. More specifically, I'm working with opencpn (https://github.com/opencpn/opencpn) where the plan is to implement this.  This means the the application:

   - Downloads and installs a tarball in user-writable paths.
   - dlopen the plugin dynamic library.
   - In some cases uses helper binary.

What are the implications if trying to do this in the sandbox (besides an evil allow=devel override for the helper binary)?

Thoughts?

--alec