Linear

1. Issues

   Creating issues with properties like status, priority, assignee, estimate, and labels.

2. Parent and sub-issues

   Breaking work into hierarchical issues.

3. Teams and workflows

   Team structure, identifiers, and configured workflow statuses.

4. Cycles

   Time-boxed sprint-like iterations and cycle planning.

5. Projects

   Grouping issues toward a deliverable with milestones and health updates.

6. Initiatives

   Higher-level goals spanning projects.

7. Triage

   Reviewing incoming issues before they enter team backlogs.

8. Custom views and filters

   Filtering, grouping, and saving views.

9. Issue properties, labels, and templates

   Status, priority, labels, estimates, and other issue properties used to organize work.

10. Insights

    Analytics on cycle time, throughput, and trends.

11. GitHub integration

    Linking pull requests and automating status changes from branches.

12. API and webhooks

    GraphQL API, API keys, OAuth, and webhooks for automation.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.