This is a fairly niche bug that most users will likely never encounter.
When a checker is created without a GC code set, it defaults to a displayed GC code of "?". However, this causes problems for the HTML link generation, since the format for a Challenge Checker link is project-gc.com/Challenges/{gc_code}/{tag_id}: the {gc_code} becomes "?", meaning that the URL becomes project-gc.com/Challenges/?/12345 and thus the tag ID gets interpreted as if it were a GET/query parameter. This is undesirable.
Demo/Steps for Reproduction
(1) Create a checker with no associated GC#. Locate it on the "My scripts and tags" page, or on the associated script's tags.
(2) Click the "Link" button to generate HTML.
(3) Notice that the generated HTML, as well as the Example link on the left, contain a "?" in the URL. This causes the URL to be interpreted as if it contained GET/query parameters.
Reason to Fix
Currently, in order to get from the "My scripts and tags" page to a particular checker's webpage, one needs to:
(1) Click the "Edit" button to open the script associated with the tag.
(2) Scroll and/or Control-F to locate the tag.
(3) Click the "Use checker" button to open the checker's page.
This is far too many clicks/scrolling for me. So, instead, when I need to open a checker page, I simply use the "Link" button to generate HTML, and then click one of the links that generates on the left.
Normally, the checker has a GC code set, so this takes me right to the checker page. But (as above) if the checker has no GC code, then it becomes "?" and messes up the URL. So then I need to go manually fix it to get to the checker page.
This was starting to get somewhat annoying, so I am now formally filing this report...
