Development versions without a unique version number, has the suffix "-dev-YYMMDD", where "dev" means development version and "YYMMDD" means the date of the last commit (change) to the source code.
Android builds were generated with ndk-build from Android NDK r21d and r22 Beta 1 (see Application.mk and Android.mk in jni directory of the zip archive for more details).
All android builds where optimized with the source independent compiler flags "-O3" and "-flto" (link time optimization). When there was source depended compiler flags (provided by the source code) for further optimization, they where used. At the end, i did a short test, what Android NDK version (r21d or r22 Beta 1) produces faster builds and that version was used.