https://waldgrave.com/basicautocorrect/privacy

Nothing is collected: no servers, accounts, analytics or tracking, and no network requests.
Typing stays local: when you finish a word, the extension reads at most the 64 characters before your cursor, checks the last word, fixes it in your browser, and forgets it immediately.
What’s saved on your device only: your settings, your corrections, your never-correct words, and the last 10 corrections (just the words, like “dont → don’t”). None of it is synced or sent anywhere.
Permissions: storage keeps those settings on your device. Site access exists only so the extension can work in the text fields where you type.
Nothing is shared or sold, and it complies with Chrome’s “Limited Use” rules and Mozilla’s add-on policies.
Removing the extension deletes all of its data.