We ship two libraries: 1. libapriltag.so This is the main library that provides the main apriltag functionality. It exports ONLY apriltag_* and tag* symbols. Normal applications should use this library only 2. libapriltag-utils.so This library provides auxiliary functionality used primarily by the apriltag examples. It provides apriltag-specific functions for reading/writing images, processing commandline options and such. This library exports more symbols, many with very generic names. Most people won't need this library The newer tag families (tagCircle49h12, tagStandard52h13, tagCustom48h12, tagStandard41h12) need binary data to function, and upstream was shipping this data inside their sources. This was resulting in very large source files that took hours to build on some architectures, producing unacceptably high build times: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=921256 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=920894 I resolve this by patching the sources to ship that data in separate binary files to be read-in at runtime from /usr/share/apriltag. These can be updated by "debian/rules tags-bindata". This is run manually (to avoid tickling the above bugs), with the results committed to the repo -- Dima Kogan , Sun, 28 Mar 2021 14:52:28 -0700