As per Appleosophy and MacRumors, the current beta for macOS Catalina no longer features the widget app, which first appeared in OS X Tiger in 2005. It includes a calendar, clock, calculator and a selection of other widgets.
Appleosophy found that Dashboard is missing from the Launchpad interface and could not force it to be activated using Terminal.
While many macOS users won't miss Dashboard if it is removed for good, there are still some fans of the app, which offered widgets in a second screen rather than the scrollable sidebar. Others may miss the app simply for how long it's been a part of the Mac desktop experience.
One of the favorites from Dashboard was Sticky notes. A user on MacRumor's forum notes that after updating to macOS Catalina the notes will be automatically imported to the Stickies app.
Probably a testament to its age, Apple's page for downloading third party Dashboard widgets indicates there are currently 1,703 Dashboard widgets spanning dozens of categories. That's many times more than the widgets on the App Store for Notification Center.