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.
To build Konpass you need Nestor80, run it like this:
N80 COMFILE.ASM KONPASS.COM
N80 DATFILE.ASM KONPASS.DAT --direct-output-write --no-string-escapes
There's also a build.sh script (for Linux and WSL) that will do that for you.
Konpass is licensed under GPLv2, as it's Compass since its sources were published.