Some synths can be tuned via MTS-ESP (see https://surge-synthesizer.github.io/tuning-guide/#mts-esp for more details). Usually, you need a separate plugin to act as an MTS-ESP source. But Helio could support MTS-ESP natively and provide an MTS-ESP source, so other plugins would work out of the box with tunings other than 12edo.
Some synths can be tuned via MTS-ESP (see https://surge-synthesizer.github.io/tuning-guide/#mts-esp for more details). Usually, you need a separate plugin to act as an MTS-ESP source. But Helio could support MTS-ESP natively and provide an MTS-ESP source, so other plugins would work out of the box with tunings other than 12edo.