The aim of the GeneXus M project is to create a lightweight, cross-platform IDE for GeneXus.
It's lightweight because you require no additional software than your operating system and the IDE itself to start developing. It's cross-platform because it runs on Linux, MacOS and Windows.
Internally, GeneXus M's IDE is just the tip of the iceberg; the IDE you work with connects to GeneXus Services, which store the Knowledgebases, generate programs and databases, compile and also deploy them.
An overview of GeneXus M has been presented at the #GX27 GeneXus Meeting. You can watch it in Spanish or English.
At this moment, November 2018, there is no GeneXus M available to download or to acces online. The GeneXus Team is working on it and a beta is expected to be released by the end of 2018.