From the 17th of July boosters will be required in Indonesia when travelling "from and to regions".
c. PPDN with air, sea, land transportation modes using private or public vehicles, crossings, and intercity trains from and to regions throughout Indonesia, the following provisions apply:
- PPDN receiving the second dose of vaccination is required to show a negative result of the rapid antigen test whose sample was taken within 1 x 24 hours or a negative result of the RT-PCR test whose sample was taken within 3 x 24 hours before departure as a condition of travel and can perform on-site third dose (booster) vaccination upon departure;
d. In particular, routine trips using land transportation modes using private or public vehicles, and trains in one urban agglomeration area/area are exempted from the travel requirements as regulated in letter c.
Source: Google Translate of 
Primary question resulting from this is to which travel this applies. Are 'regions' (daerah) a defined concept and does this only apply to travel that crosses borders of these 'regions'? Or does this apply to basically any travel outside cities?
Right now we already are in Indonesia without a booster (totally willing to get one, but as far as I am aware it's not possible to get a booster as a foreigner in Indonesia?), so stressing out a bit now in terms of what this means for our travel (getting an antigen at a lab for 40 days every day sounds... virtually impossible).