It’s always been possible to add a “View full calendar” or “View more events” link to your widgets by hard-coding it into your widget format. In 3.0, this can be done more dynamically using the new show_calendar_link option.

{<a href="|calendar_link|" target="_blank">Show Full Calendar</a>}

You can include it conditionally in your format_widget wrapper, and then customize the link destination per placement — so the same widget template might link to /admissions on one page and /athletics on another, just by passing &show_calendar_link=/athletics when you embed it.