This document describes the binary format of the Instance.Tags property.
The format of the Tags property is a list of byte sequences, where each element is separated by a null character. Each element is interpreted as a Lua string representing a tag on the instance.
For example, a list with elements "AAA", "BBB", and "CCC" would be encoded as the following byte sequence:
41 41 41 00 42 42 42 00 43 43 43
Elements are meant to be unique, and unordered. Care should be taken to make sure ordering is consistent, and that duplicates are not present.
Though extremely rare, files produced by Roblox may contain duplicate elements.