Labels in JIRA are an extremely flexible text field where multiple strings can be used across all tasks and projects. They can be created or removed by any user. They are also searchable with states similar to the typeaheads in the "project field" in phabricator: "in", "not in", "in any"...
This task is to write detailed acceptance criteria for this data field.
some external references
https://confluence.atlassian.com/display/DOC/Add,+Remove+and+Search+for+Labels
https://confluence.atlassian.com/display/JIRACLOUD/Labeling+an+Issue
https://confluence.atlassian.com/display/JIRAKB/How+to+Delete+Labels+in+JIRA