https://help.libreoffice.org/Calc/Logical_Functions#AND needs to mention that 0 and '' (empty string) is also considered as a FALSE statement.
Very likely these has to be mentioned at other logical functions
I think the functions AND/OR behave like that:
0 is FALSE, all other numbers are TRUE.
Empty cells and text in cells are ignored.
If all arguments are ignored or there are no arguments, there is an error.
Text as a direct argument (not in a cell) leads to an error.
Errors as argument lead to an error.
@gilward: yes. Will add add it to the documentation, please?
Olivier Hallot committed a patch related to this issue.
It has been pushed to "master":
tdf#99611 improve function AND() documentation