star wars - Why were the fireships trying to put out the fires on the Invisible Hand?

Thanks to this question (How could the fireships in RotS know that Grievous' flagship was crewed by friendlies?) we've learned that the fireships (firefighting speeders) knew that the Invisible Hand had been taken over by Anakin Skywalker and Ben Kenobi because they sent a message. But why were they there in the first place?

Is there any evidence to suggest that they were dousing all the ships that were crash-landing (be they friend or foe) to prevent casualties on the ground?

Answer

Non-junior novelization (Matthew Stover's) of ROTJ has this to say:

1. 
   
   

   They were there because debris from earlier battle started tons of fires.

   
   

   
   

   The dayside surface of the capital planet was shrouded in smoke from a million fires touched off by meteorite impacts of ship fragments; far too many had fallen to be tracked and destroyed by the planet's surface-defense umbrella.

   
   

   The nightside's sheet of artificial lights faded behind the red-white glow from craters of burning steel; each impact left a caldera of unimaginable death. In the skies of Coruscant now, the important vessels were no longer warships, but were instead the fire-suppression and rescue craft that crisscrossed the planet.

   
   

   
   


2. 
   

   Note the first bolded statement in the first paragraph.

   
   

   There's no suggestion that fireships were trying to put out fires on other descending fragments before, as the only approach listed was to destroy them via planet's defenses.

   
   

   This is confirmed because the first response to Invisible Hand's descent was ALSO via Surface Defense attack, until they learned it was Jedi and Sith:

   
   
   

   
   

   Now one last fragmentary ship screamed into the atmosphere, coming in too fast, too steep, pieces breaking off to spread apart and stream their own contrails of superheated vapor; banks of turbolasers on the surface-defense towers isolated their signature, and starfighters whipped onto interception courses to thin out whatever fragments the SD towers might miss, and far above, beyond the atmosphere, on the bridge of RSS Integrity, Lieutenant Commander Lorth Needa spoke urgently to a kneehigh blue ghost scanned into existence by the phased-array lasers in a holocomm: an alien in Jedi robes, with bulging eyes set in a wrinkled face and long, pointed, oddly flexible ears. "You have to stand down the surface-defense system, sir! It's General Kenobi!" Needa insisted. "His code verifies, Skywalker is with him — and they have Chancellor Palpatine!"

   
   

   
   

   They only think of fireships after getting the idea that they needed to save the ship" (e.g. fireships weren't there to prevent ground fires by extinguishing burning debris in flight):

   
   

   
   

   "First, a flight of fireships," Needa said, more calmly now. "If they don't get the burnoff under control, there won't be enough hull left to make the surface.