Flexbox alignment & ordering classes shouldn't hardcode the grid tiers

Created by: ghost

my-file.scss

    $enable-flex: true;

    $grid-breakpoints: (
      xs: 0,
      sm: 544px,
      md: 768px,
      lg: 992px
    );

    @import "../bootstrap/variables";

    @import "../bootstrap/mixins";

    @import "../bootstrap/normalize";
    @import "../bootstrap/reboot";

    @import "../bootstrap/grid";

If I remove xl from breakpoints variable, classes like

    .col-xl-top {
        align-self: flex-start;
    }

    .col-xl-center {
        align-self: center;
    }

    .col-xl-bottom {
        align-self: flex-end;
    }

still remain in compiled code... Can you please fix that or tell me what I am doing wrong?