useStrictBehavior(e, t, r) {
    var a = this.strict;
    if (typeof a == "function")
      try {
        a = a(e, t, r);
      } catch {
        a = "error";
      }
    return !a || a === "ignore" ? !1 : a === !0 || a === "error" ? !0 : a === "warn" ? (typeof console < "u" && console.warn("LaTeX-incompatible input and strict mode is set to 'warn': " + (t + " [" + e + "]")), !1) : (typeof console < "u" && console.warn("LaTeX-incompatible input and strict mode is set to " + ("unrecognized '" + a + "': " + t + " [" + e + "]")), !1);
  }
Check whether to apply strict (LaTeX-adhering) behavior for unusual
input (like `\\`).  Unlike `nonstrict`, will not throw an error;
instead, "error" translates to a return value of `true`, while "ignore"
translates to a return value of `false`.  May still print a warning:
"warn" prints a warning and returns `false`.
This is for the second category of `errorCode`s listed in the README.