bug | = B = | bug-for-bug compatible

bug-compatible adj.

[common] Said of a design or revision that has been badly compromised by a requirement to be compatible with fossils or misfeatures in other programs or (esp.) previous releases of itself. "MS-DOS 2.0 used \ as a path separator to be bug-compatible with some cretin's choice of / as an option character in 1.0."

bug | = B = | bug-for-bug compatible