IIS 4.0 and 5.0 allows remote attackers to obtain fragments of source code by appending a +.htr to the URL, a variant of the "File Fragment Reading via .HTR" vulnerability.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5104
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2000/ms00-044