`arc unit` and `arc lint` no longer prompt you before continuing if there are failures.
- See PHI2051.
In Mercurial, with certain character sets, some `arc` workflows may fail in `arc-hg` while trying to perform UTF8 operations.
- See PHI1959.
Shell completion can be trivially simplified.
- See PHI1933.
`arc unit` and `arc lint` should have more sensible ordering and summarization of results.
- See PHI1895.
- See D21660.
`arc alias` can't alias `diff`, etc.
- See PHI1869.
`arc alias` doesn't list aliases, etc.
- See PHI1857.
- See PHI1846.
`arc` may leave stdout/stderr nonblocking.
- See PHI1845.
`arc` no longer automatically provides "Depends on".
- See PHI1758.