Lead is very flexible and was used even in the last century in Germany for I think roof transitions, fresh water pipes etc. I inherited a nice town house from 1900 which still has lead pipes, but I let them install new ones so the old ones are now dead in the walls as a piece of history.
Lead flashing is still in use for roofing elsewhere in the EU. Most of the builders yards near me have rolls of it.
In the UK lead pipes were legal to install until 1970s.
I think the idea was that water pipes will build up a later of calcium anyway, so they aren't harmful.
In Germany there are probably tons of lead pipes still in existence and and only from 2026 is there a law that they all _have_ to replaced (previously they could stay as long as the water lead content was in the permitted range, but I don't think anybody ever checked).