According to Wikipedia, "DC offset... is the mean amplitude of the waveform. If the mean amplitude is zero, there is no DC bias. A waveform with no DC bias is known as a DC balanced or DC free waveform. [...] The term originates in electronics, where DC refers to a direct current voltage. In contrast, various other non-DC frequencies are analogous to superimposed alternating current (AC) voltages or currents, hence called AC components or AC coefficients."
The audio in several UFSC videos has been observed to have a pronounced amount of DC offset. It is unclear how this was done, or to what purpose.
In Audacity (or a similar program) DC offset is visible as an off-centre waveform:
DC offset in ♐FOLD. Image by Risto
It has been observed by Discord user Risto that in at least one case, "the handshake doesn't have an offset" when the rest of the audio does"
Handshake + Cd offset audio in ♐DUAL