I recently updated IPv6 Toolkit in Debian. IPv6 Toolkit is a security assessment and troubleshooting tool for the IPv6 protocols, written by Fernando Gont.

Mainly, this update prevented it from being removed from Bullseye, as compilation broke under the new GCC 10.

This is the full changelog:

ipv6toolkit (2.0+ds.1-1) unstable; urgency=medium

  * Refreshed patches using gbp pq export. Added:
    - Fixed GCC-10 compilation. Closes: #957370.
    - Silenced compilation warnings that are already fixed upstream.
    - Fixed stringop-truncation warning.
  * Bumped compat level to 12.
  * Bumped Standards-Version to 4.5.0.
    - Changed Priority to optional.
  * Disabled debian/watch.

 -- Octavio Alvarez <alvarezp@alvarezp.com>  Tue, 04 Aug 2020 23:21:55 -0500

Thanks, Luciano, for your help!