# Concepts Throughout the GitBook developer platform and its documentation, you'll encounter various concepts, variables, and terms.

Term	Description	Where to Find
`<organizationId>`	A unique identifier of an Organization in GitBook.	Found in the URL of any space or via the "Copy org ID" button in the organization settings. Example: `https://app.gitbook.com/o/<organizationId/s/<sapceId>`
`<spaceId>`	A unique identifier of a Space in GitBook.	Found in the URL of any space or via the "Copy space ID" button in the upper-right dropdown in a space. Example: `https://app.gitbook.com/o/<organizationId/s/<sapceId>`
`<userId>`	A unique identifier of a User in GitBook.	Retrieved from the "GET Current User" API endpoint or via the "Copy user ID" button from your organization settings.
`gitbook-manifest.yaml`	A required file in a GitBook integration containing metadata for publishing and developing your app. Automatically generated from the CLI when running `gitbook new`.	See the Configurations section for more info.
`.gitbook-dev.yaml`	A required file in a GitBook integration that includes configuration for local development. Automatically generated from the CLI when running `gitbook dev`.	See the Development section for more info.

### How integrations are rendered in GitBook Rendering of custom blocks is controlled in the integration's code and executed in the GitBook backend. {% @mermaid/diagram content="sequenceDiagram actor User User ->>+ GitBook: Insert block in the editor loop Every interaction with the block GitBook ->>+ Integration: Execute rendering of the block with current props & state Integration ->>- GitBook: Return ContentKit output for the block GitBook ->>- User: Render UI in the editor User -->+ GitBook: Interact with the block, updating the state or props end " %}