"It's an oft-waved banner, accompanying changes which..."
What does "oft-waved banner" mean here?
Thanks in Advance
A 'banner' is the flag that an army follows into battle.
In your sentence, it's a metaphorical banner: it might be (for instance) a slogan, or a particular idea, around which those who support the 'changes' gather.
'Oft-waved' means 'often brandished high in the air': so this isn't the first time the 'banner' has been used in this way.