Reword

README.md

@@ -441,7 +441,7 @@ end
 
 `for_gem_extension` expects as argument the namespace being extended, which has to be a class or module object.
 
-The file `lib/net/http/niche_feature/version.rb` is expected to define `Net::HTTP::NicheFeature::VERSION`.
+If it exists, the file `lib/net/http/niche_feature/version.rb` is expected to define `Net::HTTP::NicheFeature::VERSION`.
 
 Due to technical reasons, the entry point of the gem has to be loaded with `Kernel#require`. Loading that file with `Kernel#load` or `Kernel#require_relative` won't generally work. This is important if you load the entry point from the optional dasherized top-level file.