As part of the recent "Backdrop LIVE" virtual conference, we hosted a session giving a top-level overview of CiviCRM functionality and integration with Backdrop CMS.
We love using open source, and we contribute back. Two of our main tools for web development are Backdrop CMS and CiviCRM. We've contributed a variety of patches and improvements to each, and we have ported and/or maintain about 50 Backdrop modules. (Feel free to use the appropriate module's Github issue queue to report an issue, or request a feature.)
We are active in both Backdrop and CiviCRM online support channels, where we both ask and answer questions. Beyond sharing code, the community shares knowledge to educate and empower others to learn from our experience and our questions. Ask a question in the Backdrop forum or on the CiviCRM StackExchange site.
If you would like to sponsor our open source work, thank you! You can do that here.