Facebook seems to be on a roll more recently with the improvements it's been making to its official application and service as well as it's other apps like Messenger. In celebration of Mother's Day, Facebook is rumored to be testing out a temporary "Reactions" feature, but a new feature they appear to be testing within their already existing Groups section aims to make it simpler for people to find groups they may be interested in. While any user can simply enter into the Groups section within the service and find groups they might enjoy, Facebook's new Discover feature within Groups could make finding the Groups you want to participate in an easier process.
There are multiple factors that Facebook has taken into account to make this behave more favorably for users, including location. Should users be interested in checking out the Groups section of the app, Discover will be able to look at geolocation data as well as your interests and your friends' interests to pull together and deliver a list of recommended Groups for you to check out. This doesn't mean that Discover will always successfully feed you recommendations that you will like, but Discover doesn't automatically disable the ability to search through and browse for Groups on your own, and while it takes longer than simply interacting with Groups that are recommended by Discover, manually browsing and finding them on your own is ultimately going to be a more pinpointed approach.
As the feature is only in a testing phase at the moment, it's extremely limited and most users likely won't see the option available on the Groups page yet. When and if Facebook rolls this out to all users at some point is unclear, although it's reasonable to assume that if the testing goes well with the users that do have access to it, that they would want to make it available to everyone down the road. There are multiple categories that Discover is able to pull from and recommend to the user, with a total of 25, and they include things like Food, Buy & Sell, Parenting, Hobby & Leisure, Animals & pets, and more.