But... the lightning strike caused a fire. That shouldn't mean the fire is "extra hot" or something like that.
I'm disturbed, as I keep these kinds of thing in my fire safe for just such a reason.
A particularly intense house fire could exceed the parameters of one's safe.
A lightning strike can heat up the air around it because of its relatively high electrical resistance; up to 50k degrees[1].
The change in temperature (average kinetic energy of the air molecules) itself can be seen in the lighting flash (creating for split seconds an awesome "plasma channel", effectively ripping apart the molecules in its dendritic way through hundreds of MV) and consequently heard (if near enough) as a pressure wave, a quick rolling thunder rumble.
Relative to the vast amount of air around a typical lightning discharge event with its characteristic current flow [2] this "temperature" cannot sustain itself so it disperses very quickly. However under the right conditions (flammable materials, humidity etc.) this can jumpstart the chemical process of "burning". Because of the multitude of variables this ain't straightforward [3] as often depicted in movies. So, no the lightning itself cannot "damage" the integrity of a safe but the secondary effects of the environment around it i.e. continuing heat source. (For convenience I've left out the scenarios regarding possible EMP damage and its secondary effects).
[0]https://www.khanacademy.org/science/chemistry/thermodynamics...
[1]https://www.weather.gov/safety/lightning-temperature
[2]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6953689/table/e...
[3]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6953689/#!po=85...
> In the meantime, please rest assured that my home is still standing. But, if you can, please donate generously to the DEC's Ukraine Humanitarian Appeal
That doesn't mean it won't heat up.
They usually have a rating of how much fire heat they can sustain before the insides get uncomfortable for paper...