Hi. Something strange just happened which led me to this bug report which you filed in 2020 (and last touched in May 2021).
enigmail is available in bookworm right now. $ rmadison enigmail enigmail | 2:1.9.9-1~deb8u1 | oldoldoldstable | source, all enigmail | 2:2.2.4-0.2~deb10u1 | oldstable | source, all enigmail | 2:2.2.4-0.3 | stable | source, all enigmail | 2:2.2.4-0.3 | testing | source, all enigmail | 2:2.2.4-0.3 | unstable | source, all (Bug in britney?) Thanks.