Why is the subjunctive used here?

In Cicero Pro Caelio 41- I do not know why the subjunctive ‘coniveret’ is used.
‘multa enim nobis blandimenta natura ipsa genuit quibus sopita virtus coniveret interdum’
Could anyone help me out?

A final clause without ut since there is the pronoun quibus, I’d venture to say.

It’s a generic subjunctive in past sequence, just like vix posset and caperetur in the next two sentences, also in relative clauses following a main verb in the perfect (ostendit, dedit). They’re neatly composed so as to form a trio. He could have used present indicatives, but imperfect subjunctive is nicer, more nuanced (suggesting purpose or character) and more natural.
[This written independently of bedwere, whose “final” is the same as my “purpose,” but I don’t think it can be tied down so.]

multa enim nobis blandimenta natura ipsa genuit quibus sopita virtus coniveret interdum;
multas vias adulescentiae lubricas ostendit quibus illa insistere aut ingredi sine casu aliquo ac prolapsione vix posset;
multarum rerum iucundissimarum varietatem dedit qua non modo haec aetas sed etiam iam conroborata caperetur.