Sure thing Akbar – if you’re looking at a widget format (which is what I’m guessing based on the {curly brace} variable style), it looks like {gid} is used consistently across types.
If you ever need a reminder, you can use the /livewhale/?widgets_edit UI and click the buttons beneath the Format editor to have it populate in the corresponding variable name:
Ahh, the tags widget – that’s an odd case because it originally had one purpose (showing content by tag) and then a few years back we added a second purpose of “show me a list of tags” using <arg id="tag_list">true</arg> (docs). We’ll check this out and let you know what we discover.