(2 questions have both tags.)
Both tags have no tag description.
Etiquette (Cambridge Dictionary):
the set of rules or customs that control accepted behaviour in particular social groups or social situations
Manners (Cambridge Dictionary):
ways of behaving toward people, esp. ways that are socially correct and show respect for their comfort and their feelings
Wikipedia redirects manners to etiquette.
Looking at the questions, it seems like etiquette and manners are used interchangeably.
Is there are difference between etiquette and manners great enough to warrant two distinct tags? If so, what is it - where to draw the line? Else, which one should be master?