Likely refers to the quantity of entries in the file, in this case, 90,000 lines of data.
If you have encountered this file name or are mentioned within such a leak, it indicates that your credentials have been compromised through a third-party breach. HQ #6MAIL ACCESS& EDU Access D90K #6DDARK .txt
Use multi-factor authentication (MFA) on all critical accounts to prevent unauthorized access even if your password is stolen. Likely refers to the quantity of entries in