Livingstone, say, once extremely popular, welcoming folk traditions (8)
I believe the answer is:
explorer
'livingstone say' is the definition.
(I know that David Livingstone is a explorer)
'once extremely popular welcoming folk traditions' is the wordplay.
'once' becomes 'ex' (prefix meaning former or onetime).
'extremely' suggests removing the centre (only the extremes of the word are used).
'welcoming' is an insertion indicator (in sense of 'inviting in').
'folk traditions' becomes 'lore' (lore can mean traditions or stories. I am not sure about the 'folk' bit.).
'popular' with its middle removed is 'pr'.
'pr' enclosing 'lore' is 'plorer'.
'ex'+'plorer'='EXPLORER'
Can you help me to learn more?
(Other definitions for explorer that I've seen before include "Shackleton or Amundsen, say" , "Someone who visits unfamiliar areas" , "Adventurer in unknown regions" , "It helps to search" , "old satellite" .)