Shouldn't we call this methods isRegularFileOrDirectory then? I read this literally as "@return whether the file is a regular file or a directory", but my guess is it would be clearer without the parentheses. It would also be clearer if you state what is the meaning a "true" return value (by implication everything else is false). Say: @return true if the file is a regular file.

Did you consider how gitlinks and symbolic links affect this method in the future? I assume this method would return false for directories and gitlinks, but how about symblic links?