The .podspec file defines a pod. Its value spec.source is used to retrieve the actual code to build the pod, for example a Git repository.
spec.source = { :git => "https://github.com/me/myrepo.git", :tag => "v1.0.2" }
Should the .podspec itself be present in the repository?
I suppose the .podspec does not need itself to build the pod (it's a recipe for the pod, not an ingredient) but maybe it's considered a good practice to keep it in version control for some reasons.