Several proprietary parts were removed from the original Telegram client,
including Google Play Services for the location services, HockeySDK for
self-updates and push notifications through Google Cloud Messaging. Location
sharing functionality is restored using OpenStreetMap.
...
The official source code of the app contains binary blobs, so this tracks a fork
which builds those from source. Hence, versions might become available with a
certain lag.
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It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.