.BBL File Extension
File TypeBibTeX Generated Bibliography File
What is a BBL file?
Plain text file used by BibTeX, a program used to generate bibliographies; contains references defined in the LaTeX typesetting language; may be created manually or generated by BibTeX from a corresponding .BIB file.
BBL files commonly used for citing references for a LaTeX document. They are often used by academic journals and other white paper authors for storing bibliographic information.