elpa-flycheck 32~git.20200527.9c435db3-2 (amd64 binary) in ubuntu lunar

 Flycheck uses various syntax checking and linting tools to
 automatically check the contents of buffers while the user types, and
 reports warnings and errors directly in the buffer, or in an optional
 error list.
 .
 It is intended to replace the older Flymake which is part of Emacs core.