The target attribute has been obsolete since 1997. Browsers are just waiting for people to finish updating their pages to meet the new 1997 standard so they can stop supporting the attribute without breaking people’s sites. Of course using it breaks sites for the vast majority of people who prefer to decide what opens where themselves and not everyone knows enough to override that attribute so that pages always open where they want. I have fixed my browser so that it will ignore any target attributes and open pages where I want them to depending on where the link goes rather than on some attribute that has only ever annoyed people who don’t know how to reconfigure their browser.