The "Blue Line"s legal status is ‘line of withdrawal’, not a border and not a cease fire line, but it is a de-facto a border, administered by UNIFIL following UNSC1701.
The line is marked using the blue barrels, hundreds of them at every node of the line between Rosh Hanikra and the Hasbani river.
The Israeli physical barrier, be it fence or wall, is abutting the demarcated line from the south. At times it’s on the milimeter, but at times it may be several meters up to hundreds of meters from in, creating exclaves between the barrier and the Blue Line.
OSM polygon for Israel follows the barrier, which again, isn’t the recognized separation of forces, the Blue Line is.
Why was it changed several years ago, and how do we change it back?
See UNIFIL map for reference
Vs the jagged line in OSM