JANIS is not primarily a nuclear data format checking tool but it can be used to spot format coding issues in ENDF, EXFOR or any other supported format.
This can be done
Whenever you use "File > Open" to display the content of a nuclear format file a list of warnings and errors, if any, will be displayed right after reading your file(s) and before displaying content:
This is the quickest way for checking one or few files, for checking many files at once, for example a complete ENDF library, doing a "Dummy import" should be more convenient.
To check one or more data file(s) select "Import..." in JANIS "Database" menu and then follow these steps:
The "Import" progress dialog will appear:
The top part of this dialog shows progression of data files reading.
The bottom part of the dialog shows error(s) and warning(s) found (only the last ones if too many).
The errors and warnings are written in an XML log file in the folder you have specified as "Log directory", along with an XSLT file. The Import log file is named with the curent date and time, e.g. 2020-09-29-04h22h40s737.xml.
This XML file can be displayed by a browser which support XML+XSLT (e.g. Internet Explorer):