In Nepali language, those ubiquitous communal platforms with a roof, where people can sit and rest, are called "Pati".
This particular Pati is used by old Nepali peoples on their leisure playing music with different instruments, specially Hindu prayer songs. On the sign is the name of a Prayer group.
This is why it is secured with a metal grid, as it contains decorations, furniture, and maybe cases with the musical instruments.
Bhaktapur is one of the Royal Cities of Nepal, located about 10 Km East of Kathmandu.
For more info about Bhaktapur, read en.wikipedia.org/wiki/Bhaktapur.