Khalid

The former organizations from the region that had supported ETA had primarily been Direct Action (France) who had an Internationalist relationship with the struggles of Anti-Imperialist Militants that had fought for Self-Determination for their Communities; The Red Brigades; Revolutionary Cells (RZ) and the Red Army Faction.

Legal parties within Spain although are incapable of supporting ETA due to the nature of Spanish political repression. However other separatists within Spain have shown solidarity towards the Basque Struggle in the past.

'Alright, thank you. Any idea how Marxist-Leninist it actually is? '
For the most part-- While ETA has Marxist-Leninist rhetoric and upholds the National Question in relation to Socialism in One Country, ETA is primarily Left-Nationalist in the same sense that similar organizations are.
'Do they get any support from ML parties from Spain and France (or elsewhere)?'
Those whom primarily support the ETA (Other organizations) are mainly those within the same struggle that ETA has been in for a prolonged period of time; IE: PFLP, PKK (Or various other Kurdish Militant Organizations for this matter), the former INLA.

' About ETA, I know nothing about them. Like, I have no idea how much their struggle is actually supported by the Basque people etc.'

ETA is simply the Armed Paramilitary Wing of the Basque Independence Struggle; Due to this ETA is marginally smaller than various other Non-Armed Basque Movements. (As it is simply the Armed Wing as opposed to being a 'legal organization.')

Support has varied in the same sense that similar struggles have had varying support among the Community that they're representing, empowering and attempting to emancipate. (Ireland being an example with the 'RA)

Certainly though ETA is justified within their action if it is to meet a degree of civility at emancipating and empowering the Basque Proletariat against the Spanish State.

Sadly certain 'Marxist-Leninists' appear to disregard the National Question in relation to the self-determination of oppressed nationalities that are seeking to form a self-determined state in regards to Socialism in One Country.