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nchar() now gives the number of characters and their width as would be printed in Rgui for non-representable UTF-8 strings, not as they would be printed in Rterm (via <U+xxxx> escapes).
memory.size() no longer wraps around allocations greater than 2Gb. (PR#11596)
The 'factor' method of format() now preserves names, dims and dimnames in the same way as for character and numeric inputs. (PR#11512)
plot(<table>) now uses a sensible default main title.
qf() no longer gives NaN when one of df1 and df2 is large and the other is infinite (including if both are infinite); it is more accurate e.g. for qf(1e-18, 2,4).
qbeta(-1e10, 50, 40, log.p=TRUE) no longer hangs.