In Odoo there is a concept of Account Tag. What is the meaning of those? Note that Account tag is a different concept than Analytical Accounting tags. 

Accounts tags can be a seen by first enabling the developer mode and then accessing Accounting -> Configuration -> (Menu group Accounting) -> Account tags. And there are a lot of them. For example in Mexican locale some 1080 ready-created Account tags are available. And multiple Account tags can be applied to a single Account (in the Chart of Accounts).

Acount tags can also be applied to either Accounts or Taxes. What is the meaning of this?