There does not appear to be a way to read this value using the API. Logic to iterate through all jobs already exists in crawl control but this is based on all jobs listed in the WAIL UI, which should be all in the Heritrix jobs/ directory but I am not 100% sure of that.
The Browsertrix.cloud service from Webrecorder recently demoed some ways to effectively represent this information. You might look to inspiration there, though the real estate is a bit tighter.
There does not appear to be a way to read this value using the API. Logic to iterate through all jobs already exists in crawl control but this is based on all jobs listed in the WAIL UI, which should be all in the Heritrix
jobs/
directory but I am not 100% sure of that.