They are backups of your system and add-ons that are created when you apply an update.
You only need them if you want to roll back to a previous version if something goes wrong. If all is well you can just keep the latest ones.
I highly recommend you look into implementing one of these options to automate regular backups that copy off your system. If you don’t have access to the system because of a catastrophic failure it is difficult (or impossible in the case of storage failure) to recover the backups from the file system. Also some of those options will delete old versions for you automatically and say only keep the last 7 or whatever you specify.
Thanks for the response, Google Drive setup and running now.
Funny thing is, just after I installed it I realised I had to roll back todays update, it broke HomeKit and Yeelight, they both went red and “retrying setup”. After the panic calmed down it let me use the partial from earlier today.
Will have to see if anyone else is reporting it before I try and update again.
Never mind, looks like the HomeKit one was an old hub that got plugged in again. And the Yeelights needed a power off/on.