I went to see what this proposal meant and ran into undefined jargon in groff_char.7. Yes, info groff probably tells me more than I want to know. Still, I expect the man page to be terse, but intelligible.
What's an "entity"? Fortunately, Dave Kemper's post shed light on this question. The first use of .char that came to mind was .char \[ntilde] \o'n~' which would collide badly with the following ancient trick for unbreakable, unpaddable space. (Ignore the question of whether the tilde at hand is usable as a diacritical.) .tr ~ a~b~c This, I guess, is typical of the motivation for the change. Suppose the change isn't made? What does .char do for you that .ds doesn't? Certainly nothing essential in the example above. However, it can avoid the ugliness of string invocations. I regard the potential benefit mentioned in the last sentence as unpersuasive, but the potential catastrophe of the initial example as tilting the scales toward the proposal. . Doug