Kaspersky Blog – 9.8.23
For popular messengers such as Telegram, Signal and WhatsApp, there are quite a few alternative clients (not to be confused with clients as in (human) customers; whoever opted this confusing language needs a good talking to) out there. Such modified apps — known as mods — often provide users with features and capabilities that aren’t available in the official clients.
Source: Spyware versions of Telegram and Signal on Google Play