The codec-agnostic counterpart to image/heic-sequence: a HEIF container holding several coded images without committing to HEVC in particular.
Tools disagree about which of the two to report for the same file, so it is worth accepting both. On Linux the file command tends to say image/heif-sequence where a browser file input expects image/heic-sequence.
File types
.heifs.hif
Also appears as
Not known to appear as any other types