This apps/ directory is set aside to hold interpreters that may be incorporated into NuttX.
This is DIY port of Ficl (the Forth Inspired Command Language). See http://ficl.sourceforge.net/. It is a DIY port because the Ficl source is not in that directory, only an environment and instructions that will let you build Ficl under NuttX. The rest is up to you.
The Mini Basic implementation at apps/interpreters derives from version 1.0 by Malcolm McLean, Leeds University, and was released under the Creative Commons Attibution license. I am not legal expert, but this license appears to be compatible with the NuttX BSD license see: https://creativecommons.org/licenses/. I, however, cannot take responsibility for any actions that you might take based on my understanding. Please use your own legal judgement.