Bech32 detects as much as 4 errors (within the sense that, in case you make as much as 4 substitution errors, the ensuing string is assured to have an incorrect checksum). However error detection is just not the identical as error finding: simply understanding {that a} bech32 is inaccurate doesn’t imply you’ll be able to inform the place the errors had been made.
Bech32 additionally permits correcting as much as 2 substitution errors. That’s, if you understand not more than 2 substitution errors had been made, you’ll be able to for any given string compute what the unique, legitimate, string was. The javascript code on the web site you hyperlink to has code to do that, however for security causes, it deliberately doesn’t reveal what errors it discovered, solely the place.
The reason being that correcting is harmful. If the person made greater than 2 substitution errors, the error correction algorithm might effectively nonetheless discover two errors to “right”, within the sense that it will assemble a legitimate handle, however it can not be the person’s handle. An inattentive person might effectively simply make the corrections prompt by the algorithm, and ship funds into the void. As an alternative, the correction algorithm continues to be used beneath the hood, however solely the placement of its errors is revealed, forcing the person to nonetheless go verify whether or not major supply they acquired the handle by, however maybe with additional give attention to the actual places the algorithm believes are the probably positions errors had been made.