A Provisional Administrative Line is a de facto

De facto

De facto is a Latin expression that means "concerning fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." It is commonly used in contrast to de jure when referring to matters of law, governance, or...

border

Border

Borders define geographic boundaries of political entities or legal jurisdictions, such as governments, sovereign states, federated states and other subnational entities. Some borders—such as a state's internal administrative borders, or inter-state borders within the Schengen Area—are open and...

 between two countries. For example, part of the border between Ethiopia

Ethiopia

Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...

 and Somalia

Somalia

Somalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...

is a Provisional Administrative Line.
The point at issue with Somalia was the Ogaden region, an area that Mogadishu claimed as part of the historical Somali nation that had been seized by the Ethiopians during the colonial partition of the Horn of Africa. In fact, Ethiopia's only undefined boundary was the border it shared with the former Italian Somaliland. On maps drawn after 1950, this boundary is termed "Administrative Line"