*Disclaimer, this is based off my experience and research with neps but others may have found something different or have different experiences.*
Basal shoots are growths off the BASE (hence the name) of the plant stalk (not sure if that's the right term for neps). Sometimes they will pop off easily (or can be cut) and can start putting down their own roots - though removing basals is generally not the preferred route for propagating nepenthes. To my knowledge only very vigorous species are propagated with basals as there is a higher risk of losing one or both pieces by messing with the plant at the base. Most people propagate neps by taking cuttings of the stalk from the top down and cutting vines from growth points originating from higher up on the main stalk (again not at the base).
Basal buds on N. Sanguinea
N. Sanguinea basal being rooted
Point where popped off base
Hope this helps.
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“You are beautiful, but you are empty,” he went on. “One could not die for you. To be sure, an ordinary passerby would think that my rose looked just like you--the rose that belongs to me.”