Command-line utility QLI is removed in Firebird 5.0, in accordance with its deprecation announcement published in the Firebird 4.0 release notes.

API import library for Embarcadero (former Borland) compilers fbclient_bor.lib is no longer distributed in Firebird 5.0 packages for Windows x86 platform. Anyone affected by this change may generate it using the implib.exe utility supplied with Embarcadero (former Borland) development tools as documented here.