Though the app is now open sourced, it is still difficult for a an independent person to confirm that code in the repo is same the code used for the production app. Reproducible build is a standard to ensure both are same by comparing cryptographic hashes.
Here is a guide for how telegram accomplished the same https://core.telegram.org/reproducible-builds
@tachyons play store has an older version (1.1.3) this repo has 1.2.0
This is important, I think it should be prioritized.
Here's another guide on the same : Signal
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Here's another guide on the same : Signal