In the project page I noticed you reported the following features:
I would be curious to know how CTags and Cscope would apply to your extension. For example, is any tag generation involved? Is it possible to generate a Cscope compliant database?
That's a really old description unfortunately and I should change it. It was written before Microsoft's Language Server Protocol (https://microsoft.github.io/language-server-protocol/) was a thing. These days VHDL-Tool is mostly used as a language server.
VHDL-Tool provides equivalent functionality to ctags and cscope through the language server. It's still possible to generate a ctags file with the vhdl-tool ctags subcommand but I wouldn't recommend it. It's not possible to generate a cscope compliant database.