Open source – as in “free software” https://en.wikipedia.org/wiki/Free_software this keeps development healthy by increasing interconnectedness and bringing in serendipity. The Open licences are the “lock” that keep the first two in place, what we have ain’t perfect, but they do expand the area of “trust” that a project needs to work, creative commons is a start here.
Open “industrial” standards – this is a little understand but core open, its what the open internet and WWW are built from. Here is an outline https://en.wikipedia.org/wiki/Open_standard
Open process – this is the most “nebulous” part, examples of the work flow would be wikis and activity streams. Projects are built on linking trust networks so open process is the “glue” that binds the links together. https://en.wikipedia.org/wiki/Process
To support this server and the OMN project https://opencollective.com/open-media-network