Typosquatting is related to misspellings in web addresses. Mandiant Advantage Attack Surface Management (MA-ASM) uses user-provided domains (Seeds) and common top-level domains (TLDs) to identify potential typosquat domains that are registered with malicious intent.
The tlds-alpha-by-domain.txt file provides a list of TLDs that are used for discovery of typosquatted domains in MA-ASM.