A field name is the unique, user-visible identifier for a field for Team Foundation Server. This uniqueness encourages consistency across all team projects and work item types in a specific Team Foundation Server.
Use field names when you construct queries or work in the work item type editor. Any field that is referenced in the workflow or forms section of the work item type definition must have a <FIELD> element that defines it in the <FIELDS> section.
Fields can be renamed; for example, from "Title" to "Headline," by a Team Foundation Server administrator.
Because fields can be renamed, the integrations should not refer to fields by name. Therefore, integrations and internal representations of fields should use the field reference name instead of depending on the field name itself.
Because field names are scoped to Team Foundation Server, renaming a field in a single work item type affects all work item types defined in all team projects.
Field names can be up to 128 Unicode characters in length. The following Unicode characters are not allowed:
Leading or trailing spaces
Two or more sequential spaces
Opening and closing square brackets