It’s a “fork” of D&D 5e: based on similar fundamentals, but having split from the main branch of 5e development and thereafter developed independently of 5e. In a sense, it is not all that different from Pathfinder’s relationship to 3.5e (though, of course, the history in Pathfinder’s case is a little more involved).
A fork is its own thing, whatever its relationship is to the original base. It should be tagged heroes-and-dragons. I note that, like D&D itself, Heroes & Dragons uses the ampersand rather than the word “and,” which might be more accurately rendered as
-n- in our tagging system since ampersands are not allowed in that context for technical reasons, but since we use dungeons-and-dragons rather than dungeons-n-dragons it’s probably better to spell it out here.
But the long and short of it is that someone who knows D&D 5e but has never played Heroes & Dragons shouldn’t be answering Heroes & Dragons questions—you don’t have the expertise necessary to know if your answer is still accurate in Heroes & Dragons, which may have changed things relative to D&D 5e. It may be possible to mix Heroes & Dragons content with D&D 5e content—much as many players do with Pathfinder and D&D 3.5e content—in which case a combination of the two tags can be used, but as in the dnd-3.5epathfinder case, a dnd-5eheroes-and-dragons question should only be answered by those who have experience with both systems, and ideally with playing the two together—experience with one or the other should be considered insufficient.