How do Fontaines D.C. achieve tape-style saturation?

The gear guide identifies the Strymon Deco, also named as the Strymon Deco Tape Saturation & Doubletracker, as their tool for this texture. Those names refer to the same pedal family, rather than necessarily two separate effects.

Tape-style saturation recreates the soft compression and harmonic grit associated with pushing recording tape. It can round off sharp peaks and give guitars a thicker, slightly roughened edge. The supplied guide doesn’t specify their settings.

There’s also a Strymon Deco Plugin for software-based processing, but the supplied material doesn’t establish that the band use it.