What defines the sign of transistor rating values?
The - (or +) sign indicates polarity (voltage) or direction (current).

For voltages you choose a - (negative or reference) and a + (positive) node.

For current you choose a direction.

Either polarity or direction is fine but you must be consistent, so stick with that choice.

Here the two manufacturers chose opposite polarities and current directions. That's fine (makes no difference) as long as they're clear about it.

For NPN transistors I have never seen negative voltage ratings like for some manufacturers do for PNPs. That makes sense because an NPN needs a positive Vbe voltage (Vbase > Vemitter) to make it work in active mode.

For a PNP it is the reverse, all polarities are reversed. To make a PNP work (in active mode) Vbe needs to be negative (Vbase &lt; Vemitter). We could call a PNP's Vbe not Vbe but Veb but that would complicate things in comparison to the NPN. It is much easier to just make Vbe negative and all other voltages (Vce_max etc..) negative as well.

So in my opinion using negative voltage ratings for a PNP is "more correct". However some people may get confused about these negative values and then there is nothing wrong with using positive values and just changing the polarities.