From <https://www.theregister.com/2020/06/05/windows_10_microsoft_defender_smartscreen/>: A developer of a Windows utility has protested that "Microsoft Defender SmartScreen is hurting independent developers" because of the number of warnings and obstacles placed in front of users who download installers that are not signed or sufficiently well known. In the absence of a “Let’s Encrypt” equivalent for them, code-signing certificates cost money. And on top of that, SmartScreen’s warnings will not go away until that certificate has built up some (unspecified) minimum level of “reputation”. Because of this, many projects, like Ardour and Inkscape, don’t bother with signing, and rely on their users to negotiate the obstacle course of download and installation warnings.