What does the "i" (information) icon mean in Tables & Columns?

[SB87]

Is anyone able to explain what these "i" icons mean, please? How do they differ from those marked with a green icon.

[Anurag Tripathi]

I understand this is for learning and understanding purpose, but they don't seen to be doing anything. 

Only thing there I have ever used is the + ones that ar4 pretty self explanatory.

[Anand Kumar P · Accepted solution]

Hi @SB87 ,

i icon often opens a popover or tooltip that provides more details about the field which table that field is extended.

Please mark it as helpful and solution proposed if it serves your purpose.

Thanks,

Anand

[Siddhata]

The Blue information icon is used to mark an indexed field whereas a blue dot icon prefixed to the Columns that are not indexed. 

ServiceNow KB 'View Indexed fields in Tables & Columns Module'- https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0789011.