The VFP low level file functions (LLFF) can be used to open a table as a file and read/write its header. The Table Header Record Structure is documented in VFP help under Table File Structure.

It is easy to find out if a table belongs to the open Database Container (DBC) using INDBC() function. Sometimes it's necessary to check it w/o referring to DBC itself.

VFP class below allows retrieval of a ZIP file comment or a list/count of files in the ZIP archive. It uses VFP low level file functions (LLFF) to directly read the ZIP file.