I wanna debug openiddict and study it.But I encounter a lot of difficulties. I appended the openiddict source code by Add->Existing Project. Some errors occur during compilation such as Error CS0103 The name 'StringSyntaxAttribute' does not exist in the current context
Error CS8370 Feature 'nullable reference types' is not available in C# 7.3. Please use language version 8.0 or greater. And there is an exclamation on each Dependecies node
I try copy Directory.Packages.props to the solution folder but it doesn't work