Comment on "Design Documents"

[janl]

From http://books.couchdb.org/relax/design-documents/design-documents

CouchDB=92s Map Reduce queries are stored in the views field. This is how
Futon displays and allows you to edit Map Reduce queries. View indexes are=
stored on a per design doc basis, according to a fingerprint of the functi=
on=92s text contents. This means that if you edit attachments, validations,=
or any other non-view (or language) fields on the design doc, the views wi=
ll not be regenerated. However, if you change a map or a reduce function, t=
he view index will be deleted and a new index built for the new view functi=
ons.

When the term "View indexes" is used in the 3rd sentence, I am
unfamiliar with the reference. I noticed that the usage of the word
"indexes" also appears in previous chapters. Would it be possible to
add more explanation?