I connot find any refeance to dev-java/byaccj having an as-is license on the website or in the tarball what is manchined on thr website is: (http://byaccj.sourceforge.net/) * It is absolutely free; no license, no royalties, free! * Of course, thanks go to Tom Corbett for BYACC, a fine implementation of YACC. And thanks to his altruistic nature for putting it in the Public Domain. I just added the Java switch. Check the ACKNOWLEDGEMENTS file for more contributors. this seems to imply that byaccj is also intended to be public domain.
Looks like public-domain to me as well. Fixed. Thanks for the report.