I've read this BBC news story in full, but I'm still confused what the UK government is planning to do. It seems it concerns the Northern Ireland Protocol, but the specifics are unclear:
No 10 revealed on Monday that it would be introducing a new UK Internal Market Bill that could affect post-Brexit customs and trade rules in Northern Ireland.
Downing Street said it would only make "minor clarifications in extremely specific areas" - but it worried some in Brussels and Westminster that it could see the government try to change the withdrawal agreement, which became international law when the UK left the EU in January. [...]
Northern Ireland Secretary Brandon Lewis conceded it would go against the treaty in a "specific and limited way". [...]
Irish Foreign Affairs Minister, Simon Coveney, called Mr Lewis' comments "gravely concerning", adding: "Any unilateral departure from the terms of the withdrawal agreement would be a matter of considerable concern and a very serious step." [...]
That may suggest, says Catherine Barnard, Professor of Law at the University of Cambridge, that the [UK] government is looking at Article 62 of the Vienna Convention on the Law of Treaties, which enables a state to get out of its treaty obligations when circumstances change radically.
So I guess we don't know the exact text yet, but do we know in any detail in what respects is the UK planning to depart from the (previously agreed) Northern Ireland Protocol? And in what circumstances? (I'm guessing it is going to happen if negotiations on the trade agreement fail by October 15, so the UK government is probably using these pending changes as a bargaining chip, but what specific aspects of the Protocol are being [re]bargained?)