How to redefine something in BEMHTML?

gistfile1.txt

// PRJ/[...]/b-page.bemhtml

block b-page {

    default: {
        var ctx = this.ctx,
            dtype = apply(this._mode = 'doctype'),
            buf = [
                dtype,
                {
                    elem: 'root',
                    content: [
                        {
                            elem: 'head',
                            content: [
                                {
                                    tag: 'meta',
                                    attrs: { charset: 'utf-8' }
                                },
                                {
                                    tag: 'meta',
                                    attrs: { 'http-equiv': 'X-UA-Compatible', content: 'IE=edge' }  // Хочу `edge` и все!
                                },
                                {
                                    tag: 'title',
                                    content: ctx.title
                                },
                                ctx.favicon ? {
                                    elem: 'favicon',
                                    url: ctx.favicon
                                } : '',
                                ctx.meta,
                                {
                                    block: 'i-ua'
                                },
                                ctx.head
                            ]
                        },
                        ctx
                    ]
                }
            ];

        applCtxy(buf);
    }

}

gistfile2.txt

block b-page, elem head {

    content: {
        // TODO: пример переопределения только `__head`
    }

}

gistfile3.txt

block b-page, elem head {

    this.ctx && this.ctx.tag === 'meta' && this.ctx.attrs && this.ctx.attrs['http-equiv']: {
        applyCtx({
            tag : this.ctx.tag,
            attrs : {
                'http-equiv' : 'X-UA-Compatible',
                content      : 'IE=edge'
            }
        })
    }

}