It holds the list of all unassigned tickets for the sprint. The expectation is that for the tickets to get into this column, they've had enough refinement done before the sprint that they can be worked on with minimal further clarification. The tickets are ordered vertically by business rank.
For when the ticket is being actively developed. The ticket is assigned to the person doing the work, and will remain in this column until the work is complete. If the work being done is Java, then branches are made off the ticket. Tickets with branches that have a pending pull request get coloured orange, while tickets with merged pull requests are green.
When the development work is ready to test, tickets are moved into Test. It will be up to whoever in the testing team is available to assign themselves the work. If a severe defect is found, then a sub-task is created from the ticket. If the defect is not a problem for the functionality, then a new ticket is created and put on the backlog.
- Product Owner Review
The product owner gets final say over whether a unit of work is done. This column is the for the final verification by the product owner that the ticket meets the business expectation.
The product owner moves the cards to this column when they are satisfied the story is complete. When a sprint ends, any tickets not in this sprint will be moved either to the next available sprint, or into the backlog.