Short answers, pulled from the story.
De facto means "in fact" or "in reality," referring to practices or conditions that exist without formal legal recognition. It contrasts with de jure, meaning "as defined by law." A de facto government holds power without legal authority; a de facto standard dominates a market without formal adoption.
A de facto government is one that holds power through usurpation or other means not sanctioned by the constitution, contrasted with a de jure government that holds formal legal authority. Deng Xiaoping of China and Manuel Noriega of Panama are cited as examples of de facto leaders who exercised nearly total control without holding legal constitutional office.
A de facto life sentence, also called a virtual life sentence, is a finite prison term long enough that the convicted person would likely die of old age before release, or would spend the vast majority of their life in prison. It is not formally classified as a life sentence but has the same practical effect.
Australia, Japan, Mexico, and the United Kingdom all have a de facto national language with no de jure official national language. Morocco and Lebanon each have official languages plus an additional de facto national language; French holds that de facto status in both countries.
A de facto technical standard is one that achieves dominant market position through tradition, enforcement, or market power rather than through a formal standardization process. CDMA1X is given as an example of a de facto technology in cell phone communications, contrasted with GSM as a formally released standard.
Article 36 of Argentina's 1994 constitutional reform declared that any acts of force against the constitutional order are irreparably null. Those who assume constitutional powers through such acts face criminal and civil liability with no statute of limitations, and all citizens are given the right to resist them. This nullified the earlier doctrine that de facto government decrees remained binding until expressly repealed.