bug#39668: 26.2; timer-list and timer-idle-list are undocumented in the Elisp manual

[ndame]

> Why do you need to access the active timers?

I wanted only to check the existing timers, not modify them,
so I needed only read only access. I don't modify anything.

I use this to avoid starting a timer if one is started already. So I just
check the timer list for the function names if it already contains 
my function. If so then I don't start a timer, because it's already done.

So the timer list eliminates the need of me haveing to store the timer in a variable,
because the list tells me if it's already active.