The SIS-CC open source community hosts and maintains several SDMX tools. They are documented here.
The SDMX Tools and related source code are publicly stored here in GitLab under the SIS-CC group https://gitlab.com/sis-cc.
If you wish to report an issue or make a feature request, please create a new GitLab issue under each corresponding SDMX Tool’s project: e.g. here for the SDMX Power-BI Connector, or here for SDMX Matrix Generator.