Beginning with today's update, BBEdit is a sandboxed app, which is a change that Bare Bones Software needed to do because it plans to include BBEdit into the Mac App Store in the future.
Sandboxing on macOS restricts apps to the intended use, and is a protection implemented to prevent malicious software from working. BBEdit requires explicit permission to access files and folders on Mac.
To work properly, BBEdit often requires advanced access to files and folders, a problem Only Bones Software solves with a question of enabling Sandbox Access. This setting, says Bare Bones Software, will allow full functionality of BBEdit without compromising security.
Without unlimited access to your files and folders, many of BBEdit's most useful features, from basic to powerful, won't work at all; or they may misunderstand in unexpected ways. At least this prevents the ability to perform work.
To solve this basic conflict between security and usability, we have prepared a solution where BBEdit requests that you allow the same access to the files and folders that will be available for a non-sandbox version.
Therefore, the first time you start BBEdit, you will be asked to allow this access. The promotion will not be repeated; so if you refuse to allow this access and later retest, go to Application Settings and click the "Allow" button in the "Sandbox Access" section.
Due to the changes, BBEdit can no longer access support folder items in iCloud Drive, so those who previously used iCloud Drive / Application Support / BBEdit have to make some manual changes as specified in the update's notes.
The new version of BBEdit also includes a number of tweaks to the app and a whole host of bug fixes, all of which are also listed in the release notes.