The ending of Enola Holmes explained
The central mystery at the heart of Enola Holmes is kicked off by the disappearance of Enola's mother Eudoria early in the film. While Enola's older brother Sherlock arrives to investigate their mother's disappearance, Enola isn't satisfied to leave it to him, especially when she realizes her mother has left behind an encoded message intended just for her. Thinking it means Eudrioa wants Enola to come after her, Enola sets out on a quest to follow the clues and solve the mystery of her mother's disappearance.
Eventually, Enola's sleuthing leads her to a warehouse on Limehouse Lane, marked with her mother's distinctive purple ribbon. Inside, Enola finds fliers for a meeting of the National Society for Woman's Suffrage, along with a pamphlet headed "Protest, Unrest, & Civil Disobedience," containing instructions for constructing an Orsini bomb. Moments later, Enola uncovers crates of these bombs within the warehouse, and worries about what her mother has gotten herself involved in.
We never actually learn the specifics of what Eudoria's women's suffrage group was planning, but it's safe to assume that it was dangerous and highly illegal. When Eudoria visits Enola at the end of the movie, she remains vague about the specifics of her plans, but does mention that she didn't tell Enola where she was going because it wasn't safe, adding that "You've got to make some noise if you want to be heard." Since we never hear of any sort of explosion or attack in Enola Holmes, it seems probable that whatever Eudoria was planning is still in the works.