(e.g., a technical part, a legal case, a genetic marker, or a specific document).

(e.g., a summary, a technical report, or an explanatory article).

It looks like a unique serial number, a database entry, or perhaps a localized product code. To help me write the "proper piece" you're looking for, could you provide a bit more context? Specifically, it would be helpful to know:

(e.g., a specific website, a textbook, or an internal company portal).