Is documentation of institutional sabbatical/release approval required as part of the ATLAS notice of intent?

No. The Notice of Intent submission includes only the cover page and the project summary.  The proposal must provide a letter from the submitting institution (see RFP section IV.B.5) specifying the release to be provided, inclusive of the ATLAS-funded release and institutional matched time. In addition, the proposal must document that the campus has met the mandatory 1:1 salary match for any ATLAS salary request (see RFP section II.F). Internal campus documents approving an applicant’s request for release do not need to be furnished. The letter provides the institution’s commitment of the release and the budget details the matching.