The article, about what is referred to as the Jewel of the Commonwealth, i.e. the Conmonwealth of Poland-Lithuania established by the Union of Lublin in 1569, and which slightly irritatingly refers to the collar as a chain, can be viewed at:
The detailed Wikipedia article in the Order, its history and insignia, and with illustrations and appropriate links, be seen at Order of the White Eagle (Poland)
All things considered it is a something of a wonder that the collar, made for the coronation of King Stanias II Augustus in 1764, ihas survived since the Third Partition and disappearance of the state in 1795. Most of the regalia, including the historic crown itself were destroyed in early nineteenth century Prussia, and the political upheavals of Poland in the nineteenth century and of all of central Europe in the twentieth century so often resulted in the destruction of symbols of the nation.
The use of the collar between 1921 and 1939 and its proposed use again are somewhat reminiscent of the French Presidency and the investing of an incoming President with the collar of the Legion of Honour - although in the case of M. Macron the Bonapartist insignia was hudgedctoo fragile to be remixed from its case and actually worn. Similarly in Brazil the President of the Republic is ex-officious head of the Order of the Southern Cross which can only be bestowed on foreigners: like the White Eagle it is a twentieth century revival of an Order of the monarchy.
In the case of all three countries it would, of course, be better to have a reigning monarch - but the experience of a truly elective monarchy in Poland from 1572 to 1795 should warn against that particular method of choosing a sovereign.
Quite coincidentally I found a fine display of Polish royal heraldry online the other day. The first arms are those of King Augustus II and King Augustus III, and by both by clicking on the Visit link and by scrolling down a rich array of heraldic art is to be found. The site can be accessed here