29. Nothing in this Charter abrogates or derogates from any rights or privileges guaranteed by or under the Constitution in respect of denominational, separate or dissentient schools.
Other interpretive provisions of the Charter are found at sections 25-28 and 30-31. See also section 93 of the Constitution Act, 1867 regarding denominational, separate and dissentient schools.
Section 29 is merely an interpretive provision for greater certainty to ensure that section 93 of the Constitution Act, 1867 (denominational school rights and privileges) are fully guaranteed.
The denominational, dissentient and separate school rights or privileges protected under section 93 of the Constitution Act, 1867 are the product of an historical compromise crucial to Confederation and form a comprehensive code immune from Charter review. It was never intended that the Charter could be used to invalidate other provisions of the Constitution, and section 29 of the Charter is present only for greater certainty (Adler v. Ontario  3 S.C.R. 609; Ontario Home Builders’ Association v. York Regional Board of Education,  2 SCR 929; Reference re Bill 30, An Act to Amend the Education Act (Ont.) 1 SCR 1148). Section 29 has no application if, further to the terms of section 93 of the Constitution Act, 1867, a province had no publicly-funded denominational schools at the time of its entry into Canada (Trinity Western University v. Law Society of British Columbia, 2016 BCCA 423).
See also the discussion under paragraph 2(a).