Original sentence: Although it is event based it is still a model built on assumed reality rather than evidence, but it allowed greater flexibility as it allows some separation between believed events and the participants.GEDCOM uses a lineage-linked data model.In the GEDCOM lineage-linked data model, all data is structured to reflect the believed reality, that is, actual (or hypothesized) nuclear families and individuals.There is a  version called Event GEDCOM, and some software uses this.This data model is based on the nuclear family and the individual.This in contrasts with evidence models, where data is structured to reflect the discovered and supporting evidence
Edited sentence: At some point in the GEDCOM history, there was a version called Event GEDCOM, and some software uses this.Essentially this data model is based on the nuclear family and the individual.GEDCOM uses what it calls a lineage-linked data model.In the GEDCOM lineage-linked data model, all data is structured to reflect the assumed/believed reality, that is, actual (or hypothesized) nuclear families and individuals.This is somewhat in contrast to other ideas proposed and researched which are sometimes called evidence models, where data is structured to reflect the discovered and supporting evidence.This is still a model built on assumed reality rather than evidence, but it allowed greater flexibility insomuch as it allowed some separation between believed events and the participants therein