What are they?
US Treasuries are loans (bonds) from the US Government.
A yield curve is a comparison of yields from different maturity bonds.
Higher long-term yields signify stress on overall market and economic conditions
Where we are right now
The US 30 Year treasury is yielding 5%, suggesting oncoming economic hardships:
Here is a 30 year history of the 30Y US treasuries with recessions:
The 5% yield signals stress, but not a break. It depends on whether companies continue to grow earnings or not. If companies pull back on earnings, it could lead to a market hiccup.
Again, nobody knows nothing.
So What?
Watch for corporate pullback. Earnings decline across industries.
Watch for increasing unemployment.