What is meant by the expression "al-Masalih al-Mursalah"?

The concept of al-masalih al-mursalah (unrestricted public interests) was mentioned by the usuliyyun (jurists specializing in the principles of Islamic jurisprudence) in their discussions on istidlal (derivation of legal rulings), with some calling it al-istidlal wal-jawab (derivation and response). Al-Khawarizmi defined it as: "Preserving the intent of the Shari'ah by averting harm from creation." Al-Ghazali defined it as: "Finding a meaning that rationally suggests a ruling, where no agreed-upon basis exists." Ibn Burhan defined it as: "That which is not based on a universal or particular principle." It is a description for which no evidence of its validity or invalidity has been revealed, and it involves bringing about a benefit or averting harm. Examples include the actions of the Companions, such as dotting the Mushaf, Abu Bakr's appointment of Umar as his successor, and demolishing a mosque due to overcrowding, as well as the creation of coinage, the renewal of the call to prayer, imprisonment, and the establishment of administrative registers. It is nullified if it leads to a preponderant or equivalent harm.