Borland Delphi 4 packed library
BPL is a developer file format used by Borland. BPL stands for “Borland Package Library,” and the files contain dynamic-link libraries used for constructing Borland programs. BPL files are most commonly used for Borland Delphi programs, but can also be shared over multiple projects.
Learn more about .BPL files:
Search on IT Knowledge Exchange for .BPL-related questions.