What is the database format of MSYS2 Pacman package cache (msys.db, mingw32.db, etc.)?

Question

MSYS2 uses pacman as its package manager, which caches available packages locally in files /var/lib/pacman/sync/<reponame>.db (such as msys.db). What is the database format of those files?

Answer 1

"The pacman databases are normally located at /var/lib/pacman/sync. For each repository specified in /etc/pacman.conf there will be a corresponding database file located there. Database files are gzipped tar archives containing one directory for each package." (See pacman database structure)