The tag is present in Lintian version 2.104.264. That is the most recent version we know about.
For some time, Rust libraries used empty installation packages with long Provides lines in their control files to deal with peculiarities in Rust packaging. It is no longer considered acceptable because it strains our archive infrastructure.
Rust packages should not be empty and merely declare a Provides control field. Instead, please merge such packages into the main installation package.
You can see some examples here:
- https://sources.debian.org/src/rust-dbus/0.9.0-2/debian/control/ - https://sources.debian.org/src/rust-x11rb/0.7.0-1/debian/control/
The decision to burden the Rust packaging team with that extra step was made after weighing all possible alternatives.
Refer to Bug#942898, Bug#945542, and http://meetbot.debian.net/debian-rust/2020/debian-rust.2020-10-28-18.58.log.html#l-150 for details.