Tag rel with “noopener” and “noreferrer” combined means that no referrer information should be passed to the website being linked to because of noreferrer tag and also prevents the newly opened page from controlling the page that delivered the traffic.
rel="noreferrer" attribute has the same effect as the rel="noopener" attribute, and it will also prevent the referrer header from being sent to the new page.
Most modern browser support noopener, but when it is not supported, we can use noreferrer. In practical terms, it makes sense to use both of them to support older browsers. There is also no good reason to remove rel="noopener" since it doesn’t seem to have any downside and it is something widely considered.