Commentary for Berakhot 92:1

And some of them close but do not open -- like a blessing which is close to its fellow which already opened. In the first blessing and the final blessing of the reading of Sh'ma, "True and stalwart" and "Truth and belief" that even though the reading of the Sh'ma breaks them up the blessings which were before rely on them, are for them "close to their fellow."

WHO IS GOOD AND DOES GOOD. And if you ask: Why does this b’rochoh, He is good and does good, begin with ברוך isn’t it adjoining its associate, the previous b’rochoh בונה ירושלים? And we have learned that when a b’rochoh is adjacent to a previous b’rochoh it is not necessary for it to begin with ברוך. And we can answer: That it was instituted separately, not as a part of the original birchas hamozon, because of the massacred of Beitar, who were not allowed to be buried for many years. When the Roman governors eventually permitted their burial a b’rochoh was added to birchas hamozon to honor the event and the great miracle, that their bodies did not decay over a period of many years. The b’rochoh maintains its special identity by beginning with ברוך.
הטוב והמטיב is a rather long b’rochoh. Usually b’rochos of this length begin with ברוך and conclude with 'ברוך אתה ד. And if you ask: Why doesn’t it conclude with 'ברוך אתה ד? And we can answer: Because initially it was a short b’rochoh, but later after the initial enactment to recite the b’rochoh they further enacted that we should recite three times the Kingdom of Hashem. Those are 1) מהמלך הטוב (3 מלכנו (2 מלך העולם.
And three times the phrase גמול. Those are 1) הוא יגמלנו (3 הוא גמלנו (2 הוא גומלנו
And three expressions of Hashem’s goodness. Those are 1) הוא ייטיב (3 הוא מטיב (2 הוא הטיב
Tosfos now turns his attention to another b’rochoh that seems to begin with ברוך but does not conclude with ברוך. In most sidurim the first b’rochoh after the Haftorah is divided into two paragraphs. It seems that these are two separate b’rochos and that the first one begins with ברוך and the second one begins with נאמן. Tosfos explains that this is not so. And the paragraph that begins with אתה נאמן of the b’rochos of the Haftorah, which seems to be an independent b’rochoh that does not conclude with ברוך, is from the previous b’rochoh. And the reason it is written in larger letters is because in earlier times, the congregation usually stood up and declared in a loud voice, you Hashem are trusted etc. when the youngster who was reading the b’rochos of the Haftorah arrived there.

Who is the good and makes good etc. -- which is not close to its fellow, which is not the blessing on victuals but on the grave of those killed at Beitar they mandated it.