How is a static software product classified as a business asset? -

Company owns markets an old software product. Was the first of its kind, fully home grown, no long term future. But will still sell decently for probably 3-5 years. Proprietary nature precludes re engineering, so is architecturally static. No true R D possible, though can be improved in marginal ways, which clients like. So, exactly how would this product be classified as a business asset, from the perspective of management/accounting?

Because it belongs to the company.They own that and that s what they make their money off of. It s not something they owe.