Lluisr,
Yes you are right, no more development, but the user who made the rom only applied updates to the kernel if I'm not mistaken, it has Android security patch level of June 2018.
He/she displayed a link, I don't understand, but for you it must mean something, it's April Security updates.
pen+OR+status:merged" target="_blank">https://review.lineageos.org/#/q/top...+status:merged