Konpass is an assembler IDE for MSX computers, complete with debugger and monitor. Minimum system requirements are a MSX2 computer with 128K RAM (256K if you use MSX-DOS 2). Konpass means "Konamiman's Phenomenal Assembler".
Konpass is a fork of Compass, originally developed in 1995 by Compjoetania and whose last version, 1.2.09, was released in 1999 by Compjoetania TNG (yes, these were two different groups of people; see the historical versions file for the full story).
Compass was a paid product, but in 2021 it was published for free including the source code: Compass 1.2.09 repository in GitHub. Konpass was created as a set of improvements for Compass on top of these sources.
See the HowToBuild.txt file if you want to try and build Compass yourself.
Konpass is licensed under GPLv2, as it's Compass since its sources were published.