[dharmab]

In the US, the only information required to be given by a previous employer is time of employment, role, and whether the person is eligible for rehire. Reputable companies will ask and provide strictly this information only, to reduce their liability.

[milesskorpen]

This is not accurate across the board. References (inc. back channel references) are common for companies that take hiring very seriously.

[rossdavidh]

Many organizations forbid providing references, but then this policy is hard to enforce. It is weird to be asked for a reference from your current employer, though.

[dhimes]

Good context. The point GP was making was that toxic manager went out of their way to trash them.

[wahnfrieden]

Vindictive bosses/owners will do as they please

[jacquesm]

They will, but some of that is actionable.