#Generate a weston.ini file:

# WARNING Due to a bug in Yocto cache, changes in related bbappand are not detected
# Work-around:
#   bitbake weston-ini-conf -c clean ; bitbake weston-ini-conf -c cleansstate

To generate the weston.ini file:

'''
[core]
backend=drm-backend.so
shell=desktop-shell.so
'''

Just create a Variable Flag:

'''
WESTONCORE[backend]??="drm-backend.so"
WESTONCORE[shell]??="desktop-shell.so"
'''

And add it to the Variable Flag WESTONSECTION, with the name of the section:
'''
WESTONSECTION[WESTONCORE]?="core"
'''

#You can custumize weston.ini by create a weston-ini-conf.bbappend:

'''
WESTONCORE[repaint-window] ??= "34"
'''

This will generate weston.ini file:

'''
[core]
backend=drm-backend.so
shell=ivi-shell.so
repaint-window=34
'''