Further to @satikusala’s point, see here for a detailed description of the link type settings available. It is important to note that these settings work for all links of that type across the whole document. Thus if, for example, you un-ticked ‘visible’ for the ‘untitled’ link type not only would it disappear in the current map but in all map views throughout the document. You can of course, toggle these settings on and off. The styling/visibility of link types only affects their display in any views that show links or link stubs (e.g. map, timeline, outline, chart, etc.).
In the same way, a link action applies to all links using that link type.
Note too that you can change a links link type after it has been created and the link will assume the new types styling, action, etc.
Links have no label, as such, but instead use their link type as the ‘label’. You can add your own link types. Once used on a single link they become just another available link type within the current document.
You can style a link individually—that is differently from its general link type—via the Browse Links dialog. My _understanding is this works akin to attribute inheritance: a link inherits all its link type’s styling except those set particular to the link.
Again, some further detail. Tinderbox is a toolbox. Everything has a default but most things can be altered by you, the user, to a default or setting that better fits your work.