The company produces several distinct but related products. All of the products have a shared set of concerns and resources. They are all built upon the same in-house operating system, they all use the same development and testing lab infrastructure, they all have UIs, automated testing, etc. Migration of CIs between teams (generally voluntary) is relatively common.
To avoid duplication of work and to coordinate work and improvements on these shared resources, "guilds" spontaneously formed. Guild members more or less represent their own team's interests while also contributing to guild efforts as a whole, if they can, and when they have the time. Each guild has semi-regular meetings. There is usually a guild "leader" but this person is more of a secretary in the sense that they only schedule meetings, take notes, and facilitate communication. Guild leaders are just CIs like everyone else in the guild and have no actual authority to direct work.
Company management is aware of guilds and will allocate resources to them if specifically requested but otherwise have no involvement in the guilds and never attend meetings. Guilds (along with non-asshat managers) are one of the things this company has that I wish was more commonplace in tech companies.