Features
Like Genres, Features are handled differently than Subjects. Features are not editable; they are "hard-wired" into the code because certain values are tied to wholesaler templates distribution templates. So, if you would like to create/update/delete features, you'll need to submit a request to TitleLeaf support. Aside: Assigning features to products, on the other hand, is nevertheless under your team's control like any other data point.
As cited in the ingestion templates, acceptable feature values during ingestion are:
Audio
Activities
Awards
Bibliography
Biography
Correlations
Glossary
Handouts
Index
Infographics
Links
Maps
Parental note
Primary source
Reviewed
Sidebars
Supplements
Table of contents
Teaching guides
Timelines
Video
The labels for these features can be overridden on the public site. Again, you'll need to submit a request to TitleLeaf support.