With Bethesda focused on Fallout 76 and Starfield, it's safe to say that The Elder Scrolls 6 is still a long ways off. Even though it's very likely that we won't learn any official details on The Elder Scrolls 6 for years, though, that won't stop the rumor mill from turning, and some even believe that we may have already learned the upcoming game's subtitle.
ZeniMax Media, the parent company of Bethesda Game Studios, filed a trademark for something called Redfall on September 10. The trademark has since come to the attention of fans, and many are assuming that the trademark is an indication of The Elder Scrolls 6's subtitle. Whether or not that's true remains to be seen, but as previously stated, it will likely be years before we find out one way or another.
If The Elder Scrolls 6 is subtitled "Redfall," then one has to wonder what exactly "Redfall" is. As far as we know, there is nothing in The Elder Scrolls lore that mentions a region called "Redfall," so it could be a reference to an event or organization instead. Alternatively, the trademark for Redfall could be completely unrelated to The Elder Scrolls, so fans should keep that in mind.
If Redfall is some new location in The Elder Scrolls universe, then it would stand in contrast to the previously presumed setting for the next game. After Bethesda released the very brief E3 2018 teaser trailer for The Elder Scrolls 6, many assumed that, based on the imagery, the next game in the series would be set in the western province of High Rock.
Considering how early The Elder Scrolls 6 is in the development process, one might dismiss the E3 2018 trailer as showing little more than a placeholder landscape. However, if Bethesda is to be believed, the setting for The Elder Scrolls 6 was decided on well before the game's announcement, so the E3 2018 trailer could very well be an accurate indication of what fans can expect from the next game in the series.
Whether The Elder Scrolls 6 is set in High Rock or somewhere called Redfall is up for debate. Ultimately, no one will know for sure until Bethesda decides to share more information, and that will likely be years from now.
The Elder Scrolls 6 is in development for unspecified platforms.