The severity level exported in checkstyle xml format is the pint severity (pint code) / pint severity levels). So Bug and Informational are exported as severity level values in the checkstyle xml.

Example:

<?xml version="1.0" encoding="UTF-8"?>
<checkstyle version="4.3">
  <file name="rule.yaml">
    <error line="289" severity="Information" message="..."></error>
...

On the other hand the defined severity levels for checkstyle are: ignore, info, warning and error.

This requires some post pint modifications on the resulting pint checkstyle xml to be able to use the xml as input for other tools, e.g. reviewdog. As these tools expect the checkstyle severity levels and are unable to handle to pint severity levels.

My suggestion is to add a simple severity mapping in the checkstyle export: