How to disable WebRTC in GeckoView

When using GeckoView, is it possible to disable WebRTC? Either programmatically or at build-time (e.g. in build.gradle)?

Context:

We are building an Android app where we would like to run mini-web-apps without internet access in a webview. When using the system webview, it's not possible to restrict internet access because the webapp can always use WebRTC to circumvent the internet restriction.

So, we are thinking about switching to GeckoView, but are not sure if this will help.

Research:

In Firefox, it seems to be possible to disable WebRTC using about:config, but in GeckoView's API, I could neither find a way to set about:config preferences, nor an API that directly disables WebRTC.

For normal internet requests, it seems to be possible to block them.

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