Trying to implement a basic case of a document folder – any Gerrit patch set containing only documents should not trigger a job. The document folder is cleverly named "doc" – any file not contained in this folder should trigger a job.
Thus, a forbidden path of "doc/**" was added, along with a forbidden path of "/COMMIT_MSG" - see config1 attachment. This screenshot shows a file path of "**", but I have also tried without this path. As mentioned above, if a file outside the doc folder is committed (with or without a document), then the job should start – thus "Disable Strict Forbidden File Verification" is enabled.
However, when a a document under the doc folder is uploaded, the job starts anyways. Eg, a patch set containing only the file "doc/somedoc.html" triggers a new job.