"json" is the survex filename stated in the 2018#03/content.json file in surveyscans/2018/ .
"svx" means that the survex file has a *ref field which states that the wallet folder holding the original notes is 2018#03
These validation concerns are generated by scripts check-svx.sh, check-refs.sh, check-refs.awk in the :loser: repository. See handbook "other scripts" for further documentaiotn.
These scripts and checks could all be done as internal troggle-generated pages as the data used is (mostly) present in the tables after importing the wallet images and the survex files. But doing it outside troggle means that we get feedback on errors before going through the import procedure, so gives us some earlier warning.