I am currently retrieving an old wallet. Which may have recieved btc from another wallet from around 2012/Be the old wallet. While copying in to Electrum to create a new wallet using

Import bitcoin addresses and private keys

I found that almost half of my text file is filled with

0014xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 0 scrip

What is this? Should i enter this, if so how?

The first part, After Extended private master key, is;

L3xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx etc

What should be the correct preface be to that line, when entered into Electrum.

One last question would be. What exactly does "best block at time of backup" mean?