The linter output is below (empty output means no errors).
src/util/serializer.h:0:  No copyright message found.  You should have a line: "Author: <name>"  [legal/copyright] [5]
src/util/serializer.h:485:  There shouldn't be a space between class identifier and :  [readability/identifiers] [4]
src/util/serializer.h:561:  There shouldn't be a space between class identifier and :  [readability/identifiers] [4]