When googling the error message fails
As I attempt to archive some G+ communities for posterity into some
static Jekyll sites, I ran into: Liquid Exception: Invalid scheme
format: external links
for which there were no search results. I’m
not used to error messages with no search results. it made me
feel special.
It turns out that Liquid assumes that a :
character in a post
category must be part of a URL, and replacing the :
with :
resolved the problem. Took a while to track that down. ☺