Just for reference, this takes place in one of the past timelines, not the one that we follow over the course of the show.
Miki Sayaka's funeral is today. The word spread round the cafeteria in a hush yesterday, word that though her parents were not allowing anyone but family to attend the wake, they will let her classmates come today, to pay their respects. So long as they're quiet, and will pay proper respect to the dead, they're more than welcome to come. That's not how it goes in every universe, of course, but that's how it seems to be in this one.
Given that Miki Sayaka considered herself dead and worthless since long before her heart stopped beating in her chest, perhaps there isn't much of a point in saying goodbyes to her now. At least, that's how Akemi Homura tends to look at this particular situation. But then, there's a lot about humanity that she's ceased to understand, or never understood at all. This could be that.
As usual, Homura eats alone in a distant corner of the cafeteria, in a booth pressed flush against a window. Rain patters against the glass. The dreary weather outside seems to infect the cafeteria with its own unique melancholy; the usual clamor in the cafeteria is replaced by the occasional bout of whispering among a thick, profound silence.
She nibbles unenthusiastically on umeboshi, barely noticing the hair-curling sour taste and staring off into space broodingly. Homura takes her lunch in silence as usual, without any desire for company. She does her best not to draw attention to herself. She just wants to be left alone.
Mami is dead, beheaded by the greedy maw of the Dessert Witch as she so often is. Sayaka has succumbed to corruption, died, and become Oktavia von Seckendorff. Kyouko has been killed in an unsurprisingly abortive attempt to find some trace of Sayaka in Oktavia; Homura was forced to kill the Witch in full view of Madoka, and now Madoka won't even talk to her anymore…
Another month has gone by in which Homura wasn't able to get anyone to listen to her, to take her seriously. She dreads the idea of having to take on Walpurgisnacht by herself, yet again. She dreads the idea of trying to keep Madoka from making a contract when none of the other Puellae Magi are still alive to help discourage her and Madoka won't even talk to her. Oh God, she groans mentally, pressing her cheek against the cool glass of the window and squeezing her eyes shut with a shuddering breath. This isn't going to go well.
Then, she picks up the strains of a half-whispered conversation in the booth next to hers.
"…hear about what happened to Miki?"
"Oh, yeah! They found her in a hotel room wearing nothing but her socks."
"That's not what I heard! You've been listening to Fujita-san again, haven't you?"
Homura's lip twists in a painful grimace. I don't want to listen to this. I don't want to listen to this. She was a thorn in my side, but I don't want to hear it…
Mercifully, the two students move to a less defamatory topic. "So… Are you going to the funeral?"
"Me? No. I barely even knew her. Why should I go there? And you?"
"Err… maybe. I mean, Miki was our classmate, after all."
Remembering herself, Homura draws a deep breath that only quakes a little. She sits up straight in her chair, brushes her hair out of her face, and pays the conversation going on near her no more mind. But she doesn't continue eating her lunch. Instead, Homura stares down at the contents of her bento box, and counts the beats of her heart, thinking.
The memories are faint and fuzzy, tipped into the sea of memory alongside all information irrelevant to maintaining the façade and the struggle to defeat Walpurgisnacht and save Madoka from her fate. That's the most reliable way to stay somewhat sane, after all, to discard everything that doesn't matter and try to forget about it. But Homura does remember faintly, if she strains her mind, having attended Sayaka's funeral in early timelines.
Even in the first timeline… Well, Homura can't actually remember having known Sayaka in the first timeline. Madoka had gravitated towards Mami and was spending significantly less time with her childhood friend than she used to. Homura may well have not actually met Sayaka in the first timeline, apart from the first day of school when everyone was introducing themselves to her.
It would be more accurate to say that, from the time when they had first met, Homura and Sayaka had never been friends. Sayaka was suspicious of Homura and constantly expressing her dislike of anyone who was secretive or not a "team player." Homura found Sayaka's holier-than-thou attitude and self-righteousness, both of which only grew worse with each timeline, intensely grating. But they were possessed of a shared affection for Madoka, and, like Madoka, Sayaka's fate was in flux; in none of the timelines Homura has visited has Sayaka ever already contracted by the time Homura arrives. So, she in her naïveté thought, perhaps Sayaka could be saved as well.
And in those early timelines, when Sayaka inevitably died, if there was a funeral before the coming of Walpurgisnacht, Homura attended it.
There's not much left she can remember about those funerals. A cold room. The smell of flowers. A woman crying—Sayaka's mother, maybe. The pounding of rain on the roof. Homura doesn't remember her emotions, what she felt to see Sayaka's picture on the bier.
Somewhere along the line, she stopped going. Homura's not sure when, but she thinks it was about the time when she decided that Sayaka wasn't worth saving.
It occurs to Homura, as she picks up her chopsticks and dabs apathetically at her salmon, that neither Kyouko nor Mami were ever given proper funerals. They both tended to die inside a Witch's barrier, the result of that being that they left no body behind. But even when they didn't, those two girls died as they had lived: forgotten. Kyouko had no family left to notice she was gone, and if Mami still had kin, they certainly never made their presence known after her death.
Was Madoka ever given a funeral? Perhaps she might have been in the first timeline, if Walpurgisnacht did not destroy the world and her body survived the great and powerful Queen of Witch's onslaught. But not in most of the others. In most of the others, Madoka had either died in a Witch's barrier or become the Witch of Mercy herself, and presumably destroyed the world. There's not much opportunity for a funeral under those circumstances.
And was I given a funeral, in any of those timelines? Did anyone ever notice that I had gone missing? Did anyone care? Or did I go out the same way Kyouko and Tomoe Mami did, completely forgotten by the world at large?
Sayaka… Sayaka is probably the only one of them who has ever gotten a funeral. She almost certainly is.
Homura pops an umeboshi into her mouth and chews hard. She won't be going to Sayaka's funeral, she resolves firmly, for she and Sayaka were not friends and, in all honesty, Homura did not know Sayaka at all beyond knowing of what happened to her once she contracted. Attending the funeral would be meaningless, under those circumstances. Miki Sayaka has enough mourners, has enough recognition of her death; she's the only Puella Magi Homura's ever known to be so privileged. Sayaka's funeral certainly won't suffer for Homura's absence.
And in her heart, in that brittle, ill-used thing, Homura doesn't want any reminder that she once considered Sayaka worth saving.