formatdb calls such as [1] capture the build time. The build time is captured in [2] and written out in [3]. [1] https://sources.debian.net/src/metastudent-data/latest/Makefile.am/#L24 [2] http://sources.debian.net/src/ncbi-blast%2B/latest/c%2B%2B/src/objtools/blast/seqdb_writer/writedb_impl.cpp/#L78-L87 [3] http://sources.debian.net/src/ncbi-blast%2B/latest/c%2B%2B/src/objtools/blast/seqdb_writer/writedb_files.cpp/#L267
Our notes about issues affecting packages are stored in notes.git and are targeted at packages in Debian in 'unstable/amd64' (unless they say otherwise).