Bugzilla keywords are labels (or tags) that can be applied to individual issues (aka tickets, bugs, reports) to annotate, classify or otherwise describe them in a structured manner.
Keywords are distinct from Components and other classification mechanisms in Bugzilla:
Components are per product, Keywords are global.
An issue can only belong to one Component at a time, but an issue may have multiple Keyword's.
Here is a current list of FreeBSD Bugzilla Keywords including their descriptions for use and the number of issues labelled with that keyword.
Content based keywords
These keywords reflect issue subject, content or substance, rather than issue states or properties.
Component based keywords
These keywords reflect the domain, area or part an issue is about or related to. 1
Hardware based keywords
These keywords reflect issues about specific hardware.
Process based keywords
These keywords reflect metadata, states or properties of the issue objects themselves (not its subject or contents) as they move through the FreeBSD triage and issue management workflow and process
This keyword is deprecated2. Remove [patch] from Summary and remove keyword:patch, no comment necessary.
This keyword is deprecated2. Remove [patch] from Summary and remove keyword:patch-ready, no comment necessary.
These should be Components. See Issue #191430: Add Components for common, popular or major Base subsystems (1)
See Issue #227147: Remove keywords: needs-staging, patch, patch-ready (2 3)