Nothing surprising about this, but it's interesting. And the RNC is small potatoes compared to, say, Amazon...
This is slightly technical, but I think it's pretty easy reading regardless of your technical background.

https://www.upguard.com/breaches/the-rnc-files


Quote In what is the largest known data exposure of its kind, UpGuard’s Cyber Risk Team can now confirm that a misconfigured database containing the sensitive personal details of over 198 million American voters was left exposed to the internet by a firm working on behalf of the Republican National Committee (RNC) in their efforts to elect Donald Trump.

...
Starting with the potential voter’s first and last names—limiting even the barest possibility of the data sets masking the identities of those described—the files go onto list a a great deal more data, including the voter’s date of birth, home and mailing addresses, phone number, registered party, self-reported racial demographic, voter registration status, and even whether they are on the federal “Do Not Call” list. Also included as data fields are the “modeled ethnicity” and “modeled religion” of the potential voter