StackStorm was an open-core project with a paid enterprise offering on top of it, belonging to a single vendor.
In 2019 the project was donated to the Linux Foundation as a neutral umbrella, also open-sourcing the enterprise features like RBAC, LDAP, UI Workflow Designer.
Today StackStorm has an open-source ecosysem with several partner companies (5) providing consulting, commercial support, custom solutions or training for the clients that may need it: https://stackstorm.com/partners/
These partners also contribute back to the core and help supporting the project together with the other maintainers.