> [Introduced](https://gitlab.com/gitlab-org/gitlab/merge_requests/17819) in GitLab 12.6.
This file lives in
`/var/log/gitlab/gitlab-rails/exceptions_json.log` for Omnibus GitLab
packages or in `/home/git/gitlab/log/exceptions_json.log` for installations
from source.
It logs the information about exceptions being tracked by `Gitlab::ErrorTracking` which provides standard and consistent way of [processing rescued exceptions](https://gitlab.com/gitlab-org/gitlab/blob/master/doc/development/logging.md#exception-handling).
Each line contains a JSON line that can be ingested by Elasticsearch. For example:
| `/child_epic <epic>` | | | ✓ | Add child epic to `<epic>`. The `<epic>` value should be in the format of `&epic`, `group&epic`, or a URL to an epic. ([Introduced in GitLab 12.0](https://gitlab.com/gitlab-org/gitlab/issues/7330)) **(ULTIMATE)** |
| `/remove_child_epic <epic>` | | | ✓ | Remove child epic from `<epic>`. The `<epic>` value should be in the format of `&epic`, `group&epic`, or a URL to an epic. ([Introduced in GitLab 12.0](https://gitlab.com/gitlab-org/gitlab/issues/7330)) **(ULTIMATE)** |