Brix forms have two levels of tabs, distinguished by name in the documentation:
List tabs — tabs above the list that switch between the different lists of the same form. Each list tab has its own filter, columns and buttons; the first one is the default and opens with the form. The documentation describes them in the List tabs section, each further list tab on its own subpage.
Data tabs — tabs of the dialog opened from the list to enter or edit a single record. They split the data of that record into pages (e.g. ~ BASIC ~, ~ MATERIALS ~). The documentation describes them in the Data tabs section, each on its own subpage.
A form without list tabs has a single list, and a dialog without data tabs shows all the data of the record on one page.