Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
stdout: Could not parse spec file with error: can't parse specfile
stderr: error: line 1: Unknown tag: ?# Cross-distribution SLiM RPM spec.
This is the standard output and standard error for the rpkg command that was used to build the package.