Since quite a long time phpMyAdmin had embedded the bfShapeFiles library for import of geospatial data. Over the time we had to apply fixes to it to stay compatible with newer PHP versions, but there was really no development. Unfortunately, as it seems to be only usable PHP library which can read and write ESRI shapefiles.
With recent switch of phpMyAdmin to dependency handling using Composer I wondered if we should get rid of the last embedded PHP library, which was this one - bfShapeFiles. As I couldn't find alive library which would work well for us, I resisted that for quite long, until pull request to improve it came in. At that point I've realized that it's probably better to separate it and start to improve it outside our codebase.
That's when phpmyadmin/shapefile was started. The code is based on bfShapeFiles, applies all fixes which were used in phpMyAdmin and adds improvements from the pull request. On top of that it has brand new testsuite (the coverage is still much lower than I'd like to have) and while writing the tests several parsing issues have been discovered and fixed. Anyway you can now get the source from GitHub or install using Composer from Packagist.
PS: While fixing parser bugs I've looked at other parsers as well to see how they handle some situations unclear in the specs and I had to fix Python pyshp on the way as well :-).